Egg-laying hens

hen portrait

Summary

Eggs are often seen as being the least harmful, in terms of animal welfare, of all animal products. However, the amount of suffering caused to chickens in the egg industry, is at least equal to any other.

Hens may even be one of the world’s most exploited and abused animals on earth. Whether free-range or caged, they will spend the majority of their lives in dark, crowded sheds, never able to experience the freedoms of their jungle fowl ancestors.

To produce an omelette, or an egg mayo sandwich, not only means a lifetime of suffering for these sensitive, intelligent creatures, but also the horrendous suffocation of day-old male chicks.

While free-range may offer the promise of happier hens enjoying a more natural environment, this is sadly just clever marketing. The only way that you can ensure you don’t contribute to the suffering of hens and their chicks is to stop eating eggs and go vegan.

Fun facts about chickens

Chickens are sophisticated talkers – Chickens communicate with 24 to 30 vocalisations, each can be nuanced and with a distinct meaning. These calls include everything from roosters saying “I’ve found food” with an excited, rapid “tuck-tuck-tuck” to a soft, vibrating warning “errrr” that spurs little chicks to run to their mums or to flatten to the ground.1Collias NE and Collias EC. 1967. A field study of the Red Jungle Fowl in north-central India. The Condor 69(4):360-86.2Smith CL, Zielinski SL. 2014. Brainy Bird. Sci Am; 310(2):60-65.[/mfn

Chickens recognise each other’s faces – Chickens recognise a large number of other chickens, not only from within their group but outsiders, too.2Bradshaw RH. 1991. Discrimination of group members by laying hens Gallus domesticus. Behav Process.143–151.
3Bradshaw RH. 1992 Conspecific discrimination and social preference in the laying hen. Appl Anim Behav Sci.33:69–75.4D’Eath RB, Stone RJ.1999.Chickens use visual cues in social discrimination: an experiment with coloured lighting. Appl Anim Behav Sci. 62:233–242. Research has shown that they can do this even when they are shown colour slides of chickens in their flock!5Bradshaw RH, Dawkins MS. Slides of conspecifics as representatives of real animals in laying hens (Gallus domesticus) Behav Process. 1993;28:165–172.

Chickens are the closest living ancestors to Tyrannosaurus rex – You might not associate the humble chicken with the most feared and famous of all of the dinosaurs, but based on molecular research scientists have discovered that chickens are closest living relative to the T-rex.6Schweitzer, MH, Asara JM, Freimark LM, Phillips M, Cantley L. 2007.Protein Sequences from Mastodon and Tyrannosaurus Rex Revealed by Mass Spectrometry. Science. Issue 5822, pp. 280-28.

Group of chickens

Chicks talk to their mums before they have even hatched – From embryonic stage, chicks make calls to let their mum know if they’re distressed from being cold or when they’re happy. Chick brothers and sisters communicate with each other whilst still in their eggs to synchronize hatching.7Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken CAB International 51-2.

Hens are very protective of their young – A mother hen will risk her own life to save her chicks. In the wild, if a predator detects the hen’s nest she will become raucous and draw potential predators to herself in an attempt to divert attention away from her chicks.1Collias NE and Collias EC. 1967. A field study of the Red Jungle Fowl in north-central India. The Condor 69(4):360-86.

Chickens have highly sensitive beaks – Chickens’ beaks are very important in the way that they experience the world – they use them to pick up objects, preen, nest and defend against attackers. Just like our fingertips, the tip of the beak is highly sensitive. They are filled with nerve endings  for touch, pain, taste and temperature.8Gentle, MJ. J Breward J. 1986. The bill tip organ of the chicken. Agricultural and Food Research Council’s Poultry Research Centre. 79-85 9Freire R, Eastwood MA, Joyce M. 2011. Minor beak trimming in chickens leads to loss of mechanoreception and magnetoreception. J Anim Sci. 89(4): 1201-6.

Chickens can feel empathy – The ability to empathise has been associated mainly with highly intelligent species such as dolphins, great apes, elephants, pigs and dogs, but chickens can be added to that list too. Studies have shown hens displaying signs of anxiety when witnessing her chicks being distressed by a puff of air – a clear sign of a basic form of empathy.10Edgar JL, Lowe JC, Paul ES, Nicol CJ. 2011 Avian maternal response to chick distress, Royal Society, 3129-34.

Chickens have better eyesight than us – and see more colours! – Chickens have excellent eyesight, allowing them to focus close-up and far away at the same time!11Dawkins MS. 1995 How do hens view other hens—the use of lateral and binocular visual-fields in social recognition. Behaviour. 132:591. They have tetrachromatic vision, which means that chickens can see more colours than humans can, including ultraviolet light.12Ham AD, Osorio D. 2007 Colour preferences and colour vision in poultry chicks. Proc R Soc B.;274.

Chickens are as clever as monkeys! – An increasing number of studies have shown that chickens’ intelligence rivals that of dogs, primates and in some tasks, human toddlers! Chickens can count to 10,13Rugani R, Fontanari L, Simoni E, Regolin L, and Vallortigara G. 2009 Arithmetic in newborn chicks, Proc. R. Soc. B.2762451–2460. display a high level of self-control,14Abeyesinghe SM, Nicol CJ, Hartnell SJ, Wathes CM. 2011. Can domestic fowl, Gallus gallusdomesticus, show self-control? Anim Behav. 2005;70:1–11. are capable of social learning,15Johnston ANB, Burne THJ, and Rose SPR. 1998. Observational learning in day-old chicks using a one-trial passive avoidance learning paradigm. Animal Behaviour 56:1347-53. have episodic memories,16Cozzutti C, Vallortigara G. Hemispheric memories for the content and position of food caches in the domestic chick. Behav Neurosci. 2001;115:305–313. and the ability to deceive others to benefit themselves – a sign of ‘Machiavellian intelligence’.17Gyger M, Marler P. Food calling in the domestic fowl, Gallus gallus: the role of external referents and deception. Anim Behav. 1988;36(2):358–365.

Chickens outnumber humans – three to one! – There are over 23 billion chickens in the world at any one time – outnumbering humans by more than three to one. Obviously, the overwhelming majority of these are bred to produce meat or eggs for humans.18Statista.com. 2020. Number of chickens worldwide from 1990 to 2018. Available at:https://www.statista.com/statistics/263962/number-of-chickens-worldwide-since-1990/

References:
  1. Collias NE and Collias EC. 1967. A field study of the Red Jungle Fowl in north-central India. The Condor69(4):360-86.
  2. Smith CL, Zielinski SL. 2014. Brainy Bird. Sci Am; 310(2):60-65.
  3. Bradshaw RH. 1991. Discrimination of group members by laying hens Gallusdomesticus. Behav Process.143–151.
  4. Bradshaw RH. 1992 Conspecific discrimination and social preference in the laying hen. Appl Anim Behav Sci.33:69–75.
  5. D’Eath RB, Stone RJ.1999.Chickens use visual cues in social discrimination: an experiment with coloured lighting. Appl Anim Behav Sci. 62:233–242.
  6. Bradshaw RH, Dawkins MS. Slides of conspecifics as representatives of real animals in laying hens (Gallus domesticus)Behav Process. 1993;28:165–172.
  7. Schweitzer, MH, Asara JM, Freimark LM, Phillips M, Cantley L. 2007.Protein Sequences from Mastodon and Tyrannosaurus Rex Revealed by Mass Spectrometry. Science. Issue 5822, pp. 280-28.
  8. Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken CAB International51-2.
  9. Gentle, MJ. J Breward J. 1986. The bill tip organ of the chicken. Agricultural and Food Research Council’s Poultry Research Centre. 79-85
  10. Freire R, Eastwood MA, Joyce M. 2011. Minor beak trimming in chickens leads to loss of mechanoreception and magnetoreception. J Anim Sci. 89(4): 1201-6.
  11. Edgar JL, Lowe JC, Paul ES, Nicol CJ. 2011 Avian maternal response to chick distress, Royal Society, 3129-34.
  12. Dawkins MS. 1995 How do hens view other hens—the use of lateral and binocular visual-fields in social recognition. Behaviour.132:591.
  13. Ham AD, Osorio D. 2007 Colour preferences and colour vision in poultry chicks. Proc R Soc B.;274 .
  14. Rugani R, Fontanari L, Simoni E, Regolin L, and Vallortigara G. 2009 Arithmetic in newborn chicks, Proc. R. Soc. B.2762451–2460.
  15. Abeyesinghe SM, Nicol CJ, Hartnell SJ, Wathes CM. 2011. Can domestic fowl, Gallus gallusdomesticus, show self-control? Anim Behav. 2005;70:1–11.
  16. Johnston ANB, Burne THJ, and Rose SPR. 1998. Observational learning in day-old chicks using a one-trial passive avoidance learning paradigm. Animal Behaviour56:1347-53.
  17. Cozzutti C, Vallortigara G. Hemispheric memories for the content and position of food caches in the domestic chick. BehavNeurosci. 2001;115:305–313.
  18. Gyger M, Marler P. Food calling in the domestic fowl, Gallus gallus: the role of external referents and deception. Anim Behav. 1988;36(2):358–365.
  19. Statista.com. 2020. Number of chickens worldwide from 1990 to 2018. Available at: https://www.statista.com/statistics/263962/number-of-chickens-worldwide-since-1990/

Chicken chatterboxes

Whether they are warning others of danger, showing off or reassuring their young, chickens are quite the chatterboxes.

Both male and female chickens can communicate in 24 to 30 vocalisations, each with a distinct meaning. What may just sound like random clucking to us humans is actually a variety of complex, unique signals communicating a range of messages from ‘I’m hungry’, to ‘Watch out, there’s danger!’1Collias, Nicholas Joos, Martin.1953. The spectrographic analysis of sound signals of the domestic fowl. Behaviour, 5, 175–188.2Smith CL, Zielinski SL. 2014. Brainy Bird. Sci Am; 310(2):60-65.

From the embryo

The communication between a hen and her chicks starts before they’re even hatched. Right from the embryonic stage, a developing chick, still in the egg, will emit a distress signal if he or she is too cold, prompting the mother hen to move her egg to a warmer spot in the nest.3Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken. CAB International. 51-2. Chicks respond to their mother’s attentiveness by emitting pleasure calls. As the chick forms inside the egg, they are able to hear their mother’s calls and respond. These vocalisations help birds recognise their mother after hatching.4Tschanz B.T. 1978 The emergence of the personal relationship between young bird and parents. J. Anim. Breed. Genet. Suppl. 4:51–100.

This communication isn’t just limited to hens and their chicks – chicks also communicate with each other in the nest. Clicking and bill clapping sounds made during late development  help synchronise hatching, so that all of the chicks break free of their shells at approximately the same time.3Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken. CAB International. 51-2.

hen and chicks

Complex signals

Chickens use referential communication (using different signals with different meanings) associated with animals of high intelligence such as dolphins, primates, domestic dogs, pigs and some birds, such as ravens.

Whilst we may hear chickens’ communication as a cacophony of clucking, when chickens talk they actually use a whole range of different signals for different purposes, such as calls, displays and whistles. They can even use these calls to confuse or deceive other birds – a sign of Machiavellian intelligence.

The type of call that chickens use is highly dependent on their intention. Males, for instance, are more likely to make an aerial alarm call when a female is present as it increases the chances of his mate and offspring surviving.5Wilson DR, Evans CS. 2008. Mating success increases alarm-calling effort in male fowl, Gallus gallus. Anim Behav. 76:2029–2035. A male chicken may choose to stay silent when there is a rival male nearby.6Kokolakis A, Smith CL, Evans CS. Aerial alarm calling by male fowl (Gallus gallus) reveals subtle new mechanisms of risk management. Anim Behaviour. Pages 1373-1380.

The type of alarm call used will also depend on the type of threat. Different calls will be used depending on if it is an aerial or ground predator and the chickens will respond appropriately to the type of danger either by taking cover, crouching down or standing alert.7Gyger M, Marler P, and Pickert R. 1987. Semantics of an Avian Alarm Call System: The Male Domestic Fowl, Gallus domesticus. Behaviour 102(1/2):15-40.

 

Unique voices

Chickens have their own distinctive voices. Every rooster’s crow call is unique and correlates with his comb length (the feathered crest on the top of his head) – an indicator of male dominance.8Appleby MC, Mench JA, and Hughes BO. 2004. Poultry Behaviour and Welfare. CABI Publishing p.72. Males will listen to each other’s calls to assess the dominance status of other males.9Leonard ML and Horn AG. 1995. Crowing in relation to status in roosters. Animal Behaviour 49:1283-90.

As the rooster’s call is individually distinctive, he broadcasts his identity to the whole group. When a male finds food, they combine their call with rhythmic movements involving picking up and dropping the food morsel repeatedly—a signal called the tidbitting display. Hens use these calls to decide which males will provide food and, thus, with whom they want to mate.10Evans CS, Evans L.1999 Chicken food calls are functionally referential. Animal Behaviour. 58:w307–319.11Pizzari T. 2003. Food, vigilance, and sperm: the role of male direct benefits in the evolution of female preference in a polygamous bird. Behav Ecol. 14:593–601.

This selectivity about how and when to use certain calls suggests that chicken communication is shaped by social awareness, and the ability to ‘think before they act’. Years of research has only just begun to show how complex chicken communication is. What is clear is that chickens’ communication skills provide evidence of similarity with other highly intelligent complex social species, including primates.12Nicol C. 2006. How animals learn from each other. Applied Animal Behaviour Science 100:58-63.

References:
  1. Collias, Nicholas Joos, Martin.1953. The spectrographic analysis of sound signals of the domestic fowl. Behaviour, 5, 175–188.
  2. Smith CL, Zielinski SL. 2014. Brainy Bird. Sci Am; 310(2):60-65.
  3. Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken. CAB International.51-2.
  4. Tschanz B.T. 1978 The emergence of the personal relationship between young bird and parents. J. Anim. Breed. Genet. Suppl. 4:51–100.
  5. Wilson DR, Evans CS. 2008. Mating success increases alarm-calling effort in male fowl, Gallus gallusAnim Behav. 76:2029–2035.
  6. Kokolakis A, Smith CL, Evans CS. Aerial alarm calling by male fowl (Gallus gallus) reveals subtle new mechanisms of risk management. Anim Behaviour. Pages 1373-1380.
  7. Gyger M, Marler P, and Pickert R. 1987. Semantics of an Avian Alarm Call System: The Male Domestic Fowl, Gallus domesticus. Behaviour 102(1/2):15-40.
  8. Appleby MC, Mench JA, and Hughes BO. 2004. Poultry Behaviour and Welfare. CABI Publishingp.72.
  9. Leonard ML and Horn AG. 1995. Crowing in relation to status in roosters. Animal Behaviour49:1283-90.
  10. Evans CS, Evans L.1999 Chicken food calls are functionally referential. Anim Behaviour. 58:w307–319.
  11. Pizzari T. 2003. Food, vigilance, and sperm: the role of male direct benefits in the evolution of female preference in a polygamous bird. Behav Ecol.14:593–601.
  12. Nicol C. 2006. How animals learn from each other. Applied Animal Behaviour Science100:58-63.

The natural life of chickens

Junglefowl

Where do chickens descend from?

The domestic chicken (Gallus gallusdomesticus) is a subspecies of the red junglefowl of the Indian subcontinent, and to a much lesser degree the grey jungle fowl (Gallus sonneratii).1Eriksson J, Larson G, Gunnarsson U, Bed’hom B, Tixier-Boichard M, et al. 2008. Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken. PLoS Genet 4(2).

The male red junglefowl is a magnificent bird with a plumage of gold, red, brown, dark maroon and orange, with flecks of metallic green and grey. They have impressive tail feathers which can be up to 28cm long. You can still see wild red junglefowl today, where chickens originated,  in the forests of Southeast Asia, and parts of South Asia.

Jungle fowl are active early in the morning, asleep during the day and awake again from late afternoon until dusk. Much of their day would be spent foraging for insects, small snakes or lizards, or scratching at the ground looking for seeds and berries.2Savory CJ, Wood-Gush DGM, Duncan IJH. Feeding behaviour in a population of domestic fowls in the wild. Appl Anim Ethol. 1978;4:13–27.

 

When chickens were wild

The domestication of the red jungle fowl was well established as early as 8,000 years ago,3West B, Zhou BX. 1988. Did chickens go North? New evidence for domestication. J Archaeol Sci. 15:515–533. and some studies suggest it could have begun as early as 58,000 years ago.4Sawai H, Kim HL, Kuno K, Suzuki S, Goto H, Takada M, Takahata M, Satta Y, Akishinonomiya F. The origin and genetic variation of domestic chickens with special reference to junglefowls Gallus g. gallus and G. varius.

From this domestication and breeding came over 200 breeds of chicken which still exist today.5Doherty, J. 2010. The Private Life of Chickens. BBC Two. Available at: https://www.bbc.co.uk/programmes/b00t3tl1 The world’s most commonly farmed breed of chicken for meat (broiler chickens) include hybrids of breeds such as Ross, Hubbard and Cobb, while egg-laying hens can be hybrids such as the Golden Comet, Leghorn, Australorp, and Rhode Island Red, all prized for their ‘high productivity’ in egg laying.

 

Despite their long history of domestication and recent intense breeding and genetic manipulation, domestic chickens maintain many of the same traits as their wild ancestors.6Rauw WM, Kanis E, Noordhuizen-Stassen EN, Grommers FJ. Undesirable side effects of selection for high production efficiency in farm animals: a review. Livest Sci. 1998;56:15–33.7Appleby MC, Mench JA, Hughes BO. Poultry behaviour and welfare. Cambridge: CABI Publishing; 2004. In other words, they inherited their smartness from the wild red junglefowl.

For instance, the advanced mental capacities that you see in domesticated chickens today are a result of adapted responses to threats from predators, such as foxes and raptors, coupled with their need for strategies to deal with the pressure of competition in the pecking order.8Smith CL, Zielinski SL. 2014.The Startling Intelligence of the Common Chicken. Scientific American.

Red junglefowl have a hierarchical social system in which there is a ‘pecking order’ for both males and females. In the spring, at the onset of the breeding season, each of the stronger cocks maintains a territory with three to five hens. Meanwhile, young cocks live isolated in twos and threes. Roosters spend much of their time strutting their stuff, trying to impress females and providing them with food. Hens diligently watch the males, judging them on their behaviour, ability to protect and provide food and so on, and they remember past events, shunning nasty or deceptive males.8Smith CL, Zielinski SL. 2014.The Startling Intelligence of the Common Chicken. Scientific American.

The unrelenting threat from predators also dictates the junglefowl’s behaviour – they have had to evolve different strategies for different threats; as well as ways to tell other chickens about the dangers. They also choose carefully who to tell! If you live with chickens you’ll know how roosters are always watching over the hens, and a vigilant rooster may appear to never rest. He’ll scan the sky and landscape for potential predators, warning the hens when he senses danger.

A natural hierarchy

Chickens are naturally social birds who, in the wild, live together long-term as a flock in groups of four to 13 individuals of varying ages. A flock will always have a distinct hierarchy or ‘pecking order’, giving dominant individuals priority over food access and nesting locations.8Smith CL, Zielinski SL. 2014.The Startling Intelligence of the Common Chicken. Scientific American.

The purpose of the pecking order is to establish a social standing of each bird in the flock and ultimately preserve the strongest members for the survival of the flock. Differences such as body weight, comb size and social experience play a major part in where chickens fit in the pecking order.9Cloutier S ,Newberry R 2000 Recent social experience, body weight and initial patterns of attack predict the social status attained by unfamiliar hens in a new group. Behaviour. 137(6):705-726.

The pecking order begins when chickens are just six weeks old. Behaviours such as flaring feathers and bumping chests will be used to establish order amongst young chickens. Throughout their lives, social order dynamics will take place rooster to rooster, hen to hen and rooster to hen.

For a rooster to move up the social standing, he has to win a battle against the lead rooster to take his place. Defeated roosters go down the ladder, as do weak or sickly birds.

Hens have their own social ladder, headed up by the matriarchs of the flock – generally the older and stronger hens. Higher ranked hens will display warning behaviours such as pecks and feather pulling to let the lower ranked hen know she has overstepped her boundary.

When the balance is tipped in a pecking order, the results can be violent. This is especially true if a new bird attempts to join, or is introduced to the flock. Injury, weakness and illness can also be a cause for the rest of the flock to turn on a member, either in an attempt to drive them from the flock or kill them.

You can still see this pecking order at play in farmed chickens today. When a new chicken is introduced to an established flock, or one of its members is weak or injured, the outcome can be feather pecking. With ‘pet’ chickens in nice large spaces, the ‘weakest’ can escape. In factory farms there is no escape and feather pecking can cause serious injury. Chickens that are higher in the pecking order may pick on lower-ranked chickens not just by pecking at them but also by blocking their access to food, drink or enrichments.

nesting chicken

Nesting in the wild

Wild chickens lay approximately between 10 to 15 eggs a year during breeding season, which naturally would fall in spring.10Collias NE and Collias EC. 1967. A field study of the Red Jungle Fowl in north-central India. The Condor. 69(4):360-8.

To make sure that her eggs are safe, hens will leave the group and find a secluded nest site ready to lay.11Weeks CA and Nicol CJ. 2006. Behavioural needs, priorities and preferences of laying hens. World’s Poultry Science Journal. 62:296-307. Wild fowl favour tall patches of grass or under the roots of a tree to provide cover for their broods. They will often line their nests with vegetation and feathers to keep them warm and dry.12Duncan IJH, Savory CJ, and Wood-Gush DGM. 1978. Observations on the reproductive behaviour of domestic fowl in the wild. Applied Animal Ethology. 4:29-42. 62.

After laying her eggs the hen will sit on them day and night for three weeks. She will leave the nest only once a day to get food and water and dust bathe. The average size of each brood is 4-6 chicks.

Following hatching, chicks spend their early lives in close proximity to, if not under, their mother, especially in the first four days. Hens maintain their brood as a discreet unit away from other individuals in the social group.13Edgar J, Held S, Jones C, Troisi C. Influences of Maternal Care on Chicken Welfare 2016. Animals 2016, 6(1), 2. A hen will call her young to hide under her at any sign of danger and will even put herself in harm’s way to protect her chicks if she needs to.14Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken. CAB International. 159.15. Wood-Gush DGM, Duncan IJH, and Savory CJ. 1978. Observations on the social behavior of domestic fowl in the wild. Biology of Behaviour. 3(3):193-205.

In a natural situation, chicks would remain with their mothers for 5-12 weeks.

 

How long do chickens naturally live?

A chicken’s natural lifespan is usually 5-8 years and in some cases they can live 10-12 years.

Females over a year old are referred to as hens and younger females as pullets. Males over a year old are called roosters whilst younger males are referred to as cockerels.

References:
  1. Eriksson J, Larson G, Gunnarsson U, Bed’hom B, Tixier-Boichard M, et al. 2008. Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken. PLoS Genet4(2).
  2. Savory CJ, Wood-Gush DGM, Duncan IJH. Feeding behaviour in a population of domestic fowls in the wild. Appl Anim Ethol. 1978;4:13–27.
  3. West B, Zhou BX. 1988. Did chickens go North? New evidence for domestication. J Archaeol Sci. 15:515–533.
  4. Sawai H, Kim HL, Kuno K, Suzuki S, Goto H, Takada M, Takahata M, Satta Y, Akishinonomiya F. The origin and genetic variation of domestic chickens with special reference to junglefowls Gallus g. gallusand G. varius.
  5. Doherty, J. 2010. The Private Life of Chickens. BBC Two. Available at: https://www.bbc.co.uk/programmes/b00t3tl1
  6. Rauw WM, Kanis E, Noordhuizen-Stassen EN, Grommers FJ. Undesirable side effects of selection for high production efficiency in farm animals: a review. Livest Sci. 1998;56:15–33.
  7. Appleby MC, Mench JA, Hughes BO. Poultry behaviour and welfare. Cambridge: CABI Publishing; 2004.
  8. Smith CL, Zielinski SL. 2014.The Startling Intelligence of the Common Chicken. Scientific American.
  9. Cloutier S ,Newberry R 2000  Recent social experience, body weight and initial patterns of attack predict the social status attained by unfamiliar hens in a new group. Behaviour. 137(6):705-726.
  10. Collias NE and Collias EC. 1967. A field study of the Red Jungle Fowl in north-central India. The Condor. 69(4):360-8.
  11. Weeks CA and Nicol CJ. 2006. Behavioural needs, priorities and preferences of laying hens. World’s Poultry Science Journal. 62:296-307.
  12. Duncan IJH, Savory CJ, and Wood-Gush DGM. 1978. Observations on the reproductive behaviour of domestic fowl in the wild. Applied Animal Ethology. 4:29-42. 62.
  13. Edgar J, Held S, Jones C, Troisi C. Influences of Maternal Care on Chicken Welfare 2016. Animals2016, 6(1), 2.
  14. Rogers LJ. 1995. The Development of Brain and Behaviour in the Chicken. CAB International. 159.
  15. Wood-Gush DGM, Duncan IJH, and Savory CJ. 1978. Observations on the social behavior of domestic fowl in the wild. Biology of Behaviour. 3(3):193-205.

How egg-laying hens are farmed

The egg-laying hen is possibly the most abused animal on earth. Born in a hatchery without ever knowing her mother, she is forced to live most of her life indoors in a crowded shed laying 20 to 50 times the number of eggs she would naturally.

In the wild, hens would only lay 10 to 15 eggs in a whole year, but on modern-day farms hens are subjected to near constant lighting and fed high protein feed to increase egg production so they produce over 300 eggs a year. Some egg companies are pushing hens to laying 500 eggs.1Hendrix Genetics website. 2020. Hendrix Genetics shows strength of multi-species animal genetics at SPACE. [online] Available from: https://layinghens.hendrix-genetics.com/en/articles/reaching-500-eggs-brazil/ [Accessed 11 May 2020]2World Poultry website. 2016. 500 eggs in 100 weeks. 9 March 2016. [online] Available at: www.worldpoultry.net/Layers/Eggs/2015/11/500-eggs-in-100-weeks-2721812W [Accessed 11 May 2020]

After less than two years, she is deemed no longer productive, or ‘spent’, and slaughtered at a fraction of her natural lifespan.

How many eggs are eaten in the UK?

Despite the cruelty involved in the UK egg industry, people’s appetite for eggs continues to grow year on year, with over 13 billion eggs consumed in the UK in 2019.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

 

How much is the UK egg industry worth?

The UK egg market is worth over £1 billion and growing year on year.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

The egg market in the UK is dominated by a handful of major egg producers who supply all the major supermarkets.

Noble Foods is the biggest UK egg producer supplying 72 million eggs weekly4Camstrat.com. 2020. Noble Foods. Available at: https://www.camstrat.com/case-study/noble-foods/ [Accesed 22 July 2020] , which come from 340 contracted producers across the UK.5Noblefoods.co.uk. 2020. Egg Producers. Available at: https://www.noblefoods.co.uk/egg-producers/ [Accessed 22 July 2020] They also own Happy Egg – the most popular free-range egg company which supplies most of the major UK supermarkets. The largest independent UK egg producer is LJ Fairburn and Son which supplies 17 million eggs a week (884 million a year).6Fairburnseggs.co.uk. 2019. AWARD-WINNING FAIRBURN’S RECRUITS TRIO OF INDUSTRY EXPERTS. Available at: https://www.fairburnseggs.co.uk/news/46/446/Award-winning-Fairburns-recruits-trio-of-industry-experts [Accessed 22 July 2020] Another major egg producer is Bird Bros who produce 4 million eggs a week (more than 200 million a year).7Birdbroseggs.co.uk. 2020. Our story. Available at:http://birdbroseggs.co.uk/our-story/ [Accessed 22 July 2020]

Standards in the UK egg industry are overseen by a number of assurance certification schemes; the Lion Code of Practice – managed by the British Egg Industry Council (BEIC), the RSPCA assured scheme (for barn and free-range eggs) and the Soil Association for organic eggs.

These schemes all follow UK government legislation plus, in some cases, extra requirements depending on the scheme. (There are no extra requirements for the Lion Code of Practice for caged hens – in other words, basic minimum standards are approved for caged hens.)

There are currently estimated to be 41 million egg-laying hens in the UK – 42% caged, 56% free range (including three per cent organic), and two per cent barn.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

No matter whether the hen is caged, free range, barn or organic, hens are forced to endure continual suffering from birth to death.

 

Sterile beginnings

Once eggs are laid they are transferred to industrialised incubators to develop in tiered racks of trays and hatch at around 21 days. In the wild, mother hens would help their chicks to hatch but on farms, they have to do it alone, using their ‘egg tooth’ to break out of the shell.

Chicks are placed on a conveyor belt and their fate  depends on their gender and health. For male chicks and weak, sickly females, their very short lives will usually end in the hatchery at just one day old.

Healthy female chicks will receive a prophylactic vaccination, in the form of a mist or injection in the back of the neck, to protect them against diseases. They will then be transported to a ‘growing site’ to start their existence as egg layers.

Chicken hatchery

What happens to male chicks in the egg industry?

All male chicks, and weak or sickly females, are killed within 24 hours of birth and disposed of as a by-product of the industry.

It is common practice in all types of commercial egg farming – whether caged, free range, barn or organic – that male chicks are killed within a day of birth.

It is estimated that about 40 million day old chicks are killed in the UK each year by gassing. Other countries also macerate chicks (ground up by rollers or minced with fast moving blades). A grizzly end to their innocent, new lives.8Clarke P.2020. No alternatives to culling day old male chicks… yet. Available at: https://www.fwi.co.uk/livestock/poultry/layers/no-alternatives-to-culling-day-old-male-chicks-yet?name=no-alternatives-to-culling-day-old-male-chicks-yet&category_name=livestock%2Fpoultry%2Flayers. [Accessed 13 May 2020]

 

Why are male chicks killed?

In commercial chicken farming, broiler (meat) chickens are selectively bred to reach adult weight in just six weeks. They are large breasted and legged and develop very quickly for maximum productivity.

Egg-laying chickens, on the other hand, are bred to be as skinny as possible to save space and to channel all their energy into laying eggs. A male chicken of the egg-laying breed is therefore useless to the industry as he cannot lay eggs and cannot grow quickly enough to produce quality commercial meat.9Palmer, C. 2017. Laying Hens: The Inside Story. Available at: https://www.viva.org.uk/cracked-egg-industry

Hatchery

Photo: Andrew Skowron

The fate of the females

The poor females that escape the fate of early death are transported to a ‘growing site’ to live out the rest of their short existence as egg laying machines.

Transport for these day-old chicks can be traumatic. Chicks are shipped en masse, often over long distances in disposable cartons. They can often be subject to heat or cold stress as they aren’t, at such a young age, able to regulate their temperature. They are denied food and water for the duration of the journey, which can last for up to 36 hours.9Palmer, C. 2017. Laying Hens: The Inside Story. Available at: https://www.viva.org.uk/cracked-egg-industry

Female chicks never get to meet their mothers but are instead forced to grow up among other, unrelated females. Many who grow up in these utterly boring, unnatural environments will be left with enduring psychological trauma and are more likely to develop behavioural problems, such as feather pecking.10Edgar J, Held S, Jones C, Troisi C. Influences of Maternal Care on Chicken Welfare 2016. Animals 2016, 6(1), 2.

At growing sites, young birds may not be able to venture outside for up to 18 weeks, before being transferred to free-range or organic farms. If they are destined for caged systems, they never see the sky, feel fresh air on the feathers or soil under their feet. At 16-20 weeks old, pullets are mature enough to become egg-laying hens and are then transported to a farm or moved to another shed on site.

Laying hens have been genetically bred for a very high production of eggs. Modern commercial hens produce around 300 eggs a year – sometimes up to 500 – 20 to 50 times more than they would in the wild.

 

When do chickens stop laying eggs?

After one to two years of laying, the number of eggs a hen can produce starts to decline. Female layers that are no longer productive are known as ‘spent hens’ and all worn-out hens, whether conventionally farmed or organic, are slaughtered for ‘low quality’ meat when their egg production drops. Typically, this is around 72 weeks or 18 months.

 

Housing

The overwhelming majority of egg laying hens in the UK, whether caged, free-range or barn, spend much of their lives indoors in large industrial units.

There are three ways chickens bred for egg production are housed in the UK.

Enriched cage unit

Enriched cage unit

Caged

Caged hens currently make up 42 per cent of the UK market.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

Caged hens are the only major group of farmed animal in the UK to remain caged for all of their productive lives. Unable to escape the close proximity of other hens or fulfil natural behaviours, life in enriched cages, is one of boredom, desperation, frustration and suffering.

Battery cages were made illegal in the UK in 2012. These prison-like cages provided hens with approximately 550cm2 of space – about the area of a sheet of A4 paper. A hen’s average wingspan is about four times this size, and so she would spend the vast majority of her life unable to even spread her wings. Sadly the majority of the rest of the world’s egg laying hens are still kept in battery cages.

 

Enriched cages

Battery cages in the UK were replaced with ‘enriched cages’, which instead of separating hens into small cages each incarcerating five birds, the enriched cage fits between 40 and 80 hens, with a total of 600cm2 per hen of usable space. This gives hens no more than a postcard size of extra space compared to battery cages.11Assets.publishing.service.gov.uk. 2018. Code Of Practice For The Welfare Of Laying Hens And Pullets. Defra. Available at: //assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf

Birds in enriched cages will still spend a significant proportion of their time standing on sloping wire mesh floors with little room to move around or stretch their wings. They live under controlled artificial lighting – denied fresh air and sunshine.

The now-mandatory provision of enrichments such as nesting boxes, perches, dust bathing, litter areas and scratch pads is intended to allow hens to fulfil their natural behaviours such as scratching, foraging, roosting and dust bathing.

However, in many farms, although the hens technically have access to enrichments, it doesn’t mean that they’re able to use them. With up to 80 birds per cage, and aggressive territorial hens guarding enrichments, many hens never get access.

Hens in enriched cage

Enriched cages do not satisfy even the hen’s most basic behavioural and physical needs such as ground scratching and wing stretching, or activities such as walking, running, jumping, fluttering and flying. In short, there is no meaningful ‘enrichment’ in the enriched cage. 

Viva! has carried out multiple high profile investigations into caged hens in the UK. In 2015, an investigation into a Bird Bros farm, a company which supplies three million eggs a week, found injured, dead and dying birds with severe feather loss and without adequate nesting boxes.

For this reason, all of the major animal welfare organisations in the EU continue to push for a complete ban on cages – battery and enriched. After banning the battery cage, Austria, Belgium and Switzerland have all committed to phasing out enriched cages in the coming years.

All of the major UK supermarkets have either already stopped selling ‘whole’ caged eggs or have committed to stop selling them by 2025.

 

Barn ‘Percheries’ (two per cent)

barn chickens

Around two per cent of the eggs sold in Britain are intensively produced ‘barn eggs’.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

While this term conjures up the image of a rustic hen house with a few dozen hens sitting peacefully on their own nests, the truth is somewhat different. Barn eggs actually come from hens kept in huge indoor sheds called percheries where they have access to shared metal perches for roosting. They live their whole lives under artificial lighting with very little space and very little to do. The number of birds in each perchery can be up to 6,000.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

The new British Lion standard, stipulates a maximum of nine birds per square metre of usable area, with at least two enrichments per 1,000 birds. Like enriched cages, percheries must provide perches, litter and nests. Although there can be 120 hens per square metre in a particular nesting area – leading to the same problem of competition for space as enriched cages.11Assets.publishing.service.gov.uk. 2018. Code Of Practice For The Welfare Of Laying Hens And Pullets. Defra. Available at: //assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf

 

Free-range

Currently 56 per cent of egg-laying hens in the UK are considered free-range, including three per cent organic.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

The free-range egg market has been steadily growing over recent decades and has now overtaken the volume of caged eggs sold in the UK. An increasing appetite for what consumers perceive as ‘more ethical’ eggs, coupled with a decrease in the price difference, mean that free-range is now the most popular consumer choice.

 

Are free-range eggs better?

Unfortunately, ‘free-range’ means very little in terms of animal welfare.

Many free-range hens spend most of their lives in vast, stinking, overcrowded sheds, just as hens housed in barns do. Whilst free-range may make you think of happy hens living  outdoors, the reality can be tens of thousands of birds in one shed!

Chickens producing free-range eggs live much the same life as barn chickens. They are housed indoors in a perchery, which has the same requirements as barn chickens (see above).

Layer hen barn

 

How are free-range eggs different from barn eggs?

There is one key difference – eggs sold as free-range must come from hens who have access to the outdoors.

The official Lion Quality Code of practice states that ‘hens must have continuous daytime access to runs which are mainly covered with vegetation, with a maximum stocking density of 2,500 birds per hectare’.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020]. This should, in theory, allow all to leave the shed. However, the reality is that many birds never step outside.

Access to outside is through a small ‘pop hole’ and the minimum requirement is one pop hole per 800 birds.11Assets.publishing.service.gov.uk. 2018. Code Of Practice For The Welfare Of Laying Hens And Pullets. Defra. Available at: //assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf Hens can be fiercely territorial and will guard these exit holes. The sheer number of birds in a shed, coupled with dominant guarding of pop holes, means that a significant percentage of hens never go outside. One study revealed that, on average, only nine per cent of hens went outside at any given time and many never went outside at all.12Hegelund L, Sørensen JT, Kjær JB & Kristensen LS. 2005. Use of the range area in organic egg production systems: effect of climatic factors, flock size, age and artificial cover. British Poultry Science. 46 1-8

Viva!’s investigations into several free-range and barn egg farms have exposed crowded conditions and poor environmental enrichment. Viva!’s investigation into a ‘Happy Egg’ farm in 2010 revealed scrawny, and practically bald hens, many of which never ventured outside. Whilst at Rowbottom farm in Lincolnshire in 2015, Viva! uncovered shocking overcrowded conditions – some birds with extensive feather loss, dead birds and one with a presumed prolapse and a severely injured hen unable to walk.

Hens with severe feather loss

Hens with severe feather loss at Spalding Farm, a free-range farm in 2016

organic

Organic eggs make up just three per cent of the UK egg market and conjure up an image of happy backyard chickens pecking away in a farmyard orchard but is that really the true picture?

To be sold as organic in the UK, eggs must come from a farm that has been approved by a certification body. However, there are different organisations and not all have the same standards as to what makes a farm ‘organic’.

Are organic eggs more ethical?

Organic farms, like free-range and barn farms, have come under fire for housing animals in cramped conditions. Multi-tier aviary systems, where conveyor belts below the tiers remove the manure at regular intervals, are becoming more common in organic egg production.13Steenfeldt S and Nielsen BL. Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. I: egg laying, and use of veranda and outdoor area. Cambridge University Press. 1509-1517.

National standards set by the EU Organic Regulations stipulate a maximum stocking density of six hens per square metre of usable area and a maximum flock size of 3,000 birds. They are allowed 18cm (an extra 3cm) of perch space compared to barn hens and must have access to the outside through pop holes, as with free range. So, not quite the idyllic farmyard set up you might have imagined.3Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].

A Viva! investigation in 2012 into Mac’s Farm, an ‘award winning’ organic egg farm which was held as a model of the organic industry, found overcrowding and hens with feather loss. One hen had a severely deformed beak and one was lying dead on a filthy floor.

The strictest standards for organic egg production are those of the Soil Association, the UK’s largest organic assurance body. Even with their stricter criteria, the Soil Association can still certify flocks up to 2,000 birds. Under Soil Association standards, each hen is allowed a minimum of 10 square metres of space outside.14Soilassociation.org. 2020. Organic Vs. Free Range Eggs | What’s The Difference | Soil Association. Available at:https://www.soilassociation.org/organic-living/what-is-organic/organic-eggs [Accessed 17 April 2020]. This is still not ideal but it does mean that hens on Soil Association certified farms are considerably less likely to be injured or killed by other hens. However, the Soil Association’s standards are difficult to apply on farms large enough to supply the major supermarkets so people may have difficulty finding these eggs.

Routine debeaking is forbidden in organic egg production so feather pecking can be a problem. Evidence suggests that hens suffer greatly due to feather pecking when housed in flocks of more than 500.15Bestman MWP. 2003. Farm level factors associated with feather pecking in organic laying hens. Livestock Production Science.133-140. The routine, preventative use of antibiotics is also not allowed by organic standards which can cause diseases to spread more quickly, especially in larger flocks.

Of course, day old male chicks and spent hens are still slaughtered in organic systems.

 

Injuries, disease and mutilations

Feather pecking, cannibalism and debeaking

Hen with severe feather loss on perch

Another hen suffering from severe feather loss at Spalding Farm, 2016

Squashed into wire mesh cages frustrates these naturally active birds and boredom, coupled with lack of space, means a ‘pecking order’ is replaced by injurious feather pecking (IFP).

Feather pecking can commence when chicks are just a few weeks old and then develop into IFP. It can also spread rapidly within a flock as a learned behaviour. Feather pecking leads to increasingly exposed patches of skin, which becomes red and sore. A visibly open wound or blood can then drive hens to cannibalism

‘Aggressive pecking’ is directed at the head of another bird and ‘feather pecking’ is directed at the plumage. Hens will often rip out the feathers of other hens, or even peck them to death and engage in cannibalism. When hens injure and kill one another in this way, it damages the producer’s bottom line so it is in the interests of the egg industry to minimise these injuries.

Hens kept in both types of cage system are, therefore, routinely debeaked to prevent injury from aggressive cage-mates – a problem caused by the intensive conditions in which they are forced to live.

Beak deformity

The debeaking procedure (known as beak trimming in the poultry industry) involves the partial removal of the tip of a hen’s beak, a process which is performed without anaesthesia. Whilst in the past this was done with a red hot blade, causing the hen intense pain, it is now carried out with an infra-red beam whilst the chick is still in the hatchery.16BHWT.org.uk. 2020. Beak Trimming – The Facts! Available at: https://www.bhwt.org.uk/beak-trimming/ [Accessed 17 April 2020]. Debeaking is done to all egg-laying chicks whether caged, barn or free range, the only exception being organic, where beak trimming is prohibited. It is permissible  to remove up to one third of the beak in this procedure.11Assets.publishing.service.gov.uk. 2018. Code Of Practice For The Welfare Of Laying Hens And Pullets. Defra. Available at: //assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf

Despite being promoted as less painful and traumatic than hot blade trimming, studies have shown that this method still causes pain. A chicken’s beak is highly sensitive, rich in blood vessels and nerve endings. The process can lead to inactivity and loss of appetite due to the pain.17Marchant-Forde, R M, Fahey, A G and Cheng, H W (2008) Comparative effects of infrared and one-third hot-blade trimming on beak topography, behavior, and growth. Poultry Science.87: 1474-1483. The Farm Animal Welfare Committee (FAWC) refers to all beak trimming as a ‘mutilation’.18Data.parliament.uk. 2015. THE BEAK TRIMMING ACTION GROUP’S REVIEW. Available at:  http://data.parliament.uk/DepositedPapers/Files/DEP2015-0919/Beak_Trimming_Action_Group_Review_November_2015.pdf

Due to the substantial body of evidence against the humaneness of beak trimming, a ban has been discussed in the UK since early 2011. Debeaking isn’t used, or has been prohibited, in several European countries, such as  Germany, Norway, Finland, Sweden, Austria and Denmark. A UK ban has been postponed multiple times, following advice from Farm Animal Welfare Council (FAWC), until it can be demonstrated under commercial conditions that laying hens could be managed without beak trimming.

The main reason for stereotypical and aggressive behaviour in laying hens is squarely down to the unnatural way they are kept, which – even in higher welfare cases – does not truly reflect their natural state nor allow them to express all natural behaviours.

Sanctuaries which offer hens a genuinely free-range life in small flocks find that birds do not feather pick and have healthy, shining feathers.

 

Injuries

Hens kept in cages or crowded barns have barely enough space to move around and so  have little chance to exercise. This, combined with the loss of calcium due to the hundreds of eggshells a hen has to produce in her lifetime,  produces a high rate of osteoporosis and broken bones.

Keel bone (sternum) fractures in hens are one of the major welfare concerns for farmed hens. Not only do they cause them pain for weeks at a time but a fracture can limit their movement, making it difficult for them to get up to perches or protect themselves from aggressive pecking. The keel bone needs adequate calcium to ‘ossify’ but due to the large amounts of calcium needed for egg laying, hens keel bones are never able to form fully.19Riber. A, Casey-Trott T and Herskin.M The Influence of Keel Bone Damage on Welfare of Laying Hens. Frontiers in Veterinary Science. 28.

Standing on wire mesh for the entirety of their lives, hens often develop sores on their legs and feet. Also red and sore featherless patches on the breast and under the legs can develop into sores when exposed to ammonia from their urine.

An injured hen with feather loss struggles to walk

A hen with severe feather loss is barely able to walk at Alpha Farm, 2015

 

Diseases

High-density sheds, whether caged or free-range, are a breeding ground for diseases to spread rapidly. For this reason, preventative antibiotics are the norm in caged, barn and free-range chickens. Due to the underlying threat of antibiotic resistance, the UK farming industry is continually encouraged to cut down on antibiotic use. The only exception is in organic farming where the use of preventative antibiotics is not permitted.

Respiratory diseases are common in chickens and spread quickly due to high population densities. Infectious bronchitis (IB) and infectious bursal disease are two of the most commonIB will usually infect every bird in a flock once it takes hold and can lead to the deaths of a quarter of all birds in that flock.

A major and distressing cause of death in layers is egg peritonitis – infection and inflammation in the abdominal cavity. It can be caused by E. coli infection of the laying duct and if hens are unable to expel an egg, it may cause infection leading to peritonitis, especially if the egg breaks internally, providing a rich medium for bacterial growth. Prolapses may also occur, where part of the laying duct protrudes from the hen. Hens naturally peck at anything unusual and the result is that pecking from other birds can turn the prolapse into a bloody and infected wound.

Skin diseases are also common, some as a result of prolonged contact with moist, infected litter, causing ammonia burns and blisters.

Red mite infestations are a common problem in poultry, particularly in laying hens. Depending on the level of infestation, blood-sucking red mites can cause extreme skin irritations, encouraging feather pecking, cause weight loss, anaemia and, in some cases, death. Chicks and younger hens are more seriously affected by red mite infestations. Beak trimming exacerbates the problem hugely, as hens cannot groom properly.9Palmer, C. 2017. Laying Hens: The Inside Story. Available at: Cracked

Among caged birds, welfare and disease problems of all kinds are exacerbated by difficulty in inspecting birds – cages are stacked in tiers and the top and bottom layers may be both poorly lit and difficult for stock keepers to reach and see.

Avian flu

Some diseases in chickens can also be passed onto humans, with fatal consequences.

Avian influenza, or bird flu, is highly contagious and can be transmitted when an infected wild bird comes into contact with farmed poultry. Bird flu spreads quickly in crowded sheds and can come close to wiping out an entire country’s flock very quickly.

In 2003, an outbreak of the H5N8 strain in Holland led to the slaughter of 30 million chickens.20Guardian.com. 2020. New Bird Flu Case Reported In Netherlands. Available at: https://www.theguardian.com/world/2014/nov/30/bird-flu-netherlands-h5n8 [Accessed 17 April 2020]. At the time of writing, (April 2020), there has been an outbreak of highly contagious H5N8 which has spread to several European countries, including Germany, Poland, Romania and the Czech Republic.21World Health Organisation (WHO). 2020. Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2020 Available at: https://www.who.int/influenza/human_animal_interface/2020_01_20_tableH5N1.pdf?ua=1> [Accessed 17 April 2020].

Can you catch bird flu from chickens?

Like all viruses, the bird flu virus is constantly mutating and several strains at present can infect humans: including  H5N1, H7N9 and H9N2. Factory farming conditions enable flu viruses to mutate and there have been 15,000 outbreaks of H5N1 since 2005. In rare cases, bird flu can also have devastating consequences in people. Since 2003, there have been 861 reported cases  of H5N1 human infections and 455 deaths.22World Health Organisation (WHO). 2020. WHO | Faqs: H5N1 Influenza. [online] Available at: https://www.who.int/influenza/human_animal_interface/avian_influenza/h5n1_research/faqs/en/> [Accessed 17 April 2020]. Although instances of humans catching the virus are rare, it has been recorded as having a 60 per cent mortality rate in infected patients.23World Health Organisation (WHO). 2020. Increase In ‘Bird Flu’ Outbreaks – WHO/Europe Advice For Handling Dead Or Sick Birds. Available at www.euro.who.int/en/health-topics/communicable-diseases/influenza/news/news/2020/01/increase-in-bird-flu-outbreaks-whoeurope-advice-for-handling-dead-or-sick-birds> [Accessed 17 April 2020].

The World Health Organisation states: “The emergence of a new and very different influenza A virus with the ability infect people and have sustained human to human transmission, can cause an influenza pandemic.”24World Health Organisation (WHO), 2018. https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic) [accessed 11 May 2020]

 

Do eggs still have salmonella?

Salmonella is a bacteria that can be found in eggs, can cause food poisoning and in some cases prove fatal.

In response to the salmonella outbreak in the 1990s,  a vaccination programme was undertaken which now sees at least 85 percent of chickens vaccinated against one of the most common strains of salmonella (salmonella enteritidis). To be certified under the Lion Quality assurance scheme, chickens have to be vaccinated against salmonella. Despite this, in 2019 it was discovered that 25 egg-laying poultry flocks were infected and 45 people became ill after eating infected eggs.25Wasley, A., Heal, A. and Harvey, F. 2019. Dozens Of People Poisoned This Year By Salmonella-Infected British Eggs. theguardian.com. Available at: www.theguardian.com/environment/2019/sep/20/dozens-of-people-poisoned-this-year-by-salmonella-infected-british-eggs> [Accessed 17 April 2020].

Eggs

References:
  1. Hendrix Genetics website. 2020. Hendrix Genetics shows strength of multi-species animal genetics at SPACE. [online] Available from: https://layinghens.hendrix-genetics.com/en/articles/reaching-500-eggs-brazil/[Accessed 11 May 2020]
  2. World Poultry website. 2016. 500 eggs in 100 weeks. 9 March 2016. [online] Available at: www.worldpoultry.net/Layers/Eggs/2015/11/500-eggs-in-100-weeks-2721812W[Accessed 11 May 2020]
  3. Egginfo.co.uk. 2020. UK Egg Industry Data|Official Egg Info. Available at: https://www.egginfo.co.uk/egg-facts-and-figures/industry-information/data [Accessed 1 May 2020].
  4. Camstrat.com. 2020. Noble Foods. Available at: https://www.camstrat.com/case-study/noble-foods/ [Accesed 22 July 2020]
  5. Noblefoods.co.uk. 2020. Egg Producers. Available at: https://www.noblefoods.co.uk/egg-producers/  [Accesed 22 July 2020]
  6. Fairburnseggs.co.uk. 2019. AWARD-WINNING FAIRBURN’S RECRUITS TRIO OF INDUSTRY EXPERTS. Available at: https://www.fairburnseggs.co.uk/news/46/446/Award-winning-Fairburns-recruits-trio-of-industry-experts [Accesed 22 July 2020]
  7. Birdbroseggs.co.uk. 2020. Our story. Available at:http://birdbroseggs.co.uk/our-story/ [Accesed 22 July 2020]
  8. Clarke P.2020. No alternatives to culling day old male chicks… yet. Available at: https://www.fwi.co.uk/livestock/poultry/layers/no-alternatives-to-culling-day-old-male-chicks-yet?name=no-alternatives-to-culling-day-old-male-chicks-yet&category_name=livestock%2Fpoultry%2Flayers. [Accessed 13 May 2020]
  9. Palmer, C. 2017. Laying Hens: The Inside Story. Available at: https://www.viva.org.uk/cracked-egg-industry
  10. Edgar J, Held S, Jones C, Troisi C. Influences of Maternal Care on Chicken Welfare 2016. Animals2016, 6(1), 2.
  11. Assets.publishing.service.gov.uk. 2018. Code Of Practice For The Welfare Of Laying Hens And Pullets. Defra. Available at: //assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf
  12. Hegelund L, Sørensen JT, Kjær JB & Kristensen LS. 2005. Use of the range area in organic egg production systems: effect of climatic factors, flock size, age and artificial cover. British Poultry Science. 46 1-8
  13. Steenfeldt S and Nielsen BL. Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. I: egg laying, and use of veranda and outdoor area.Cambridge University Press. 1509-1517.
  14. Soilassociation.org. 2020. Organic Vs. Free Range Eggs | What’s The Difference | Soil Association. Available at:https://www.soilassociation.org/organic-living/what-is-organic/organic-eggs [Accessed 17 April 2020].
  15. Bestman MWP. 2003.Farm level factors associated with feather pecking in organic laying hens. Livestock Production Science.133-140.
  16. BHWT.org.uk. 2020. Beak Trimming – The Facts!Available at: https://www.bhwt.org.uk/beak-trimming/ [Accessed 17 April 2020].
  17. Marchant-Forde, R M, Fahey, A G and Cheng, H W (2008) Comparative effects of infrared and one-third hot-blade trimming on beak topography, behavior, and growth. Poultry Science.87: 1474-1483.
  18. Data.parliament.uk. 2015. THE BEAK TRIMMING ACTION GROUP’S REVIEW. Available athttp://data.parliament.uk/DepositedPapers/Files/DEP2015-0919/Beak_Trimming_Action_Group_Review_November_2015.pdf
  19. Riber. A, Casey-Trott T and Herskin.M The Influence of Keel Bone Damage on Welfare of Laying Hens. Frontiers in Veterinary Science. 28.
  20. Guardian.com. 2020. New Bird Flu Case Reported In Netherlands. Available at: https://www.theguardian.com/world/2014/nov/30/bird-flu-netherlands-h5n8 [Accessed 17 April 2020].
  21. World Health Organisation (WHO). 2020. Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2020Available at: https://www.who.int/influenza/human_animal_interface/2020_01_20_tableH5N1.pdf?ua=1> [Accessed 17 April 2020].
  22. World Health Organisation (WHO). 2020. WHO | Faqs: H5N1 Influenza. [online] Available at: https://www.who.int/influenza/human_animal_interface/avian_influenza/h5n1_research/faqs/en/> [Accessed 17 April 2020].
  23. World Health Organisation (WHO). 2020. Increase In ‘Bird Flu’ Outbreaks – WHO/Europe Advice For Handling Dead Or Sick Birds. Available at www.euro.who.int/en/health-topics/communicable-diseases/influenza/news/news/2020/01/increase-in-bird-flu-outbreaks-whoeurope-advice-for-handling-dead-or-sick-birds [Accessed 17 April 2020].
  24. World Health Organisation (WHO), 2018. https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic) [accessed 11 May 2020]
  25. Wasley, A., Heal, A. and Harvey, F. 2019. Dozens Of People Poisoned This Year By Salmonella-Infected British Eggs.theguardian.com. Available at: www.theguardian.com/environment/2019/sep/20/dozens-of-people-poisoned-this-year-by-salmonella-infected-british-eggs [Accessed 17 April 2020].

How egg-laying hens are killed

Most egg-laying hens live short and miserable lives. Their optimum laying capacity is reached by the time they are 1-2 years old, and most are considered ‘spent’ at around 72 weeks old.

As with broiler (meat) chickens, ‘spent’ hens are sent to slaughterhouses where several thousand birds can be killed every hour in a factory-like, high speed operation.

Over 800,000 spent hens are slaughtered every year and 92 percent of these are gassed with CO2 or with other gas mixtures.1Assets.publishing.service.gov.uk. 2019. Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. Defra. Available at:https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf> [Accessed 17 April 2020].

Killing by gas is one of the approved ‘humane’ methods of slaughter in the UK. It involves flooding a chamber filled with birds with a mixture of gasses or CO2. The killing process should take less than 2.5 minutes when hens are suffocated due to lack of oxygen.

Around 6.4 per cent of spent hens in the UK are killed by the Halal (Islamic ritual) method which allows stunning.1Assets.publishing.service.gov.uk. 2019. Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. Defra. Available at:https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf> [Accessed 17 April 2020]. To be sold as Halal, animals must be alive when their throats are cut and therefore stunning cannot be allowed to kill them.

The process used involves the painful and distressing shackling of hens upside down by their legs. They are then passed through an electric water bath to be stunned before they are killed by a cut to the throat.

The electric current in the bath must be strong enough to ensure the stun is effective. EU legislation stipulates a minimum current frequency but it has been found that currents being used are often only one quarter of that required. The result is that chickens are immobilised by a painful electric shock but remain conscious while being  slaughtered. Ineffective stunning is thought to affect 26-30 percent of chickens slaughtered under Halal certification.

Although non-stun slaughter is technically illegal due to the suffering it causes, it is given an exemption in the UK and EU in accordance with religious rites, mostly Islamic and Jewish. Hens killed using the non-stun method have their throats cut whilst fully conscious and therefore  feel the pain of the neck cut, and may remain conscious for minutes afterwards.2British Veterinary Association. 2020. Non-Stun Slaughter | British Veterinary Association. Available at: www.bva.co.uk/take-action/our-policies/non-stun-slaughter/> [Accessed 17 April 2020].

The market for Halal non-stun for egg laying hens in the UK is small – just 1.4 per cent of the total slaughter number. However, this still means that every year, over 10,000 hens in the UK have their throats cut while fully conscious.1Assets.publishing.service.gov.uk. 2019. Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. Defra. Available at:https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf> [Accessed 17 April 2020].

 

What happens to hen meat?

Meat from egg laying hens is deemed as inferior ‘quality’  and around 41 per cent goes to wholesale traders, mainly for use as pet food. Some 56 per cent is frozen and exported to EU and non-EU countries, one per cent is sent to butchers and two per cent is unknown.1Assets.publishing.service.gov.uk. 2019. Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. Defra. Available at:https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf> [Accessed 17 April 2020].

 

Chick

How are male chicks killed?

All male chicks born into the egg industry are routinely killed within a day of birth as they cannot lay eggs and are not suitable for meat production. Egg-laying chickens are a different breed from broiler (meat) chickens, which are bred to grow large breast muscle and legs within just six weeks.

It is estimated that 40 million male chicks are killed every year in the UK, along with weak or sickly females. Chicks bodies are often used as food for the pet industry and zoos – mostly for reptiles and birds of prey.3Clarke, P. 2020. No alternatives to culling day old male chicks… yet. Available at: https://www.fwi.co.uk/livestock/poultry/layers/no-alternatives-to-culling-day-old-male-chicks-yet?name=no-alternatives-to-culling-day-old-male-chicks-yet&category_name=livestock%2Fpoultry%2Flayers. [Accessed 13 May 2020]

 

The vast majority, if not all, male chicks in the UK are killed using inert gas. The gassing process is similar to that used on spent hens. It is recommended that oxygen level inside the chamber should not exceed one percent ‘to ensure that all chicks are killed as quickly and ‘humanely’ as possible.4Hsa.org.uk. 2006. Gas Killing Of Chicks In Hatcheries. Available at: https://www.hsa.org.uk/downloads/technical-notes/TN14-gas-killing-of-chicks-in-hatcheries.pdf Gassing, however, can result in gasping and head shaking, depending on the combination of gasses used, and it can take up to two minutes for chicks to die.

 

Maceration, which involves chicks being ground up by a large fast-moving grinder, was used in the past in the UK, and is still used in much of the world, including the U.S and Australia, where it is considered the ‘more humane’ option. Maceration is still permitted in the UK although the industry claims it is no longer used.

There have been concerted efforts in recent years to phase out the need for mass ‘culling’ of male chicks.

In 2018, scientists in Germany were the first to develop a non-invasive way to determine chicken embryo sex around seven days after fertilisation. This allows them to discard the male embryo eggs prior to hatching, removing the need to cull males after they’ve hatched.

Although the technology isn’t yet commercially available, it is hoped that it will be in the coming years. France and Germany have said they would work together to put an end to mass chick culling. France has committed to banning the culling of male chicks by 2021.5BBC News 2020. France to ban culling of unwanted male chicks by end of 2021. Available at: www.bbc.co.uk/news/world-europe-51301915 [Accessed 17 April 2020]. At the time of writing, April 2020, the UK has made no such commitments.

References:
  1. Assets.publishing.service.gov.uk. 2019. Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. Defra.Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf [Accessed 17 April 2020].
  2. British Veterinary Association. 2020. Non-Stun Slaughter | British Veterinary Association. Available at: www.bva.co.uk/take-action/our-policies/non-stun-slaughter/ [Accessed 17 April 2020].
  3. Clarke, P. 2020. No alternatives to culling day old male chicks… yet. Available at: https://www.fwi.co.uk/livestock/poultry/layers/no-alternatives-to-culling-day-old-male-chicks-yet?name=no-alternatives-to-culling-day-old-male-chicks-yet&category_name=livestock%2Fpoultry%2Flayers. [Accessed 13 May 2020]
  4. Hsa.org.uk. 2006. Gas Killing Of Chicks In Hatcheries. Available at: https://www.hsa.org.uk/downloads/technical-notes/TN14-gas-killing-of-chicks-in-hatcheries.pdf
  5. BBC News 2020. France to ban culling of unwanted male chicks by end of 2021. Available at: www.bbc.co.uk/news/world-europe-51301915 [Accessed 17 April 2020].

Campaigns & investigations

Cracked campaign

Our Cracked campaign pulls together the findings of a year-long investigation into the life of Britain’s laying hens to show you what life is really like for hens in since the ban on battery cages.

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Face off: Eggs

Join Juliet in seeing what happens on British factory farms in the egg industry as she comes face to face with the victims.

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Bird Brain: How chickens think & feel

Few people think about chickens as intelligent or emotional, however scientists (and people who live with hens) have learned that these birds can be cunning and wily, and can communicate in sophisticated ways that are on a par with some primates.

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