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.
Chickens recognise each other’s faces – Chickens recognise a large number of other chickens, not only from within their group but outsiders, too.3Bradshaw RH. 1991. Discrimination of group members by laying hens Gallus domesticus. Behav Process.143–151. 4Bradshaw RH. 1992 Conspecific discrimination and social preference in the laying hen. Appl Anim Behav Sci.33:69–75.5D’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!6Bradshaw 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.7Schweitzer, 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.
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.8Rogers 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.9Gentle, MJ. J Breward J. 1986. The bill tip organ of the chicken. Agricultural and Food Research Council’s Poultry Research Centre. 79-85 10Freire 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.11Edgar 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!12Dawkins 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.13Ham 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 10,14Rugani 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,15Abeyesinghe 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,16Johnston 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,17Cozzutti 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’.18Gyger 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.19Statista.com. 2020. Number of chickens worldwide from 1990 to 2018. Available at:https://www.statista.com/statistics/263962/number-of-chickens-worldwide-since-1990/
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.
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.
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.
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 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.
The life of a ‘meat chicken’ is short and brutal – from birth to death in just six to seven weeks. Selectively bred to gain weight quickly, most don’t see the light of day until they’re packed into a lorry and sent to slaughter. Their bodies are huge but their eyes still blue and their chirps the mere cheeps of a chick.
The average 42-day lifespan of a ‘meat chicken’, commonly known as a broiler, is spent inside a foul-smelling, often windowless shed with tens of thousands of other birds. As these young animals pile on the weight, their underdeveloped bones are unable to support them and many end up crippled or lame.
They often collapse onto the ammonia-rich faeces that cover the shed floor and develop painful hock burns – the scars of which are still evident on many carcasses lining the supermarket shelves.1Perkins, C. 2015. ‘Aldi chicken with hock burn sparks Twitter storm’. The Grocer. Available at: https://www.thegrocer.co.uk/food-safety/aldi-chicken-with-hock-burn-sparks-twitter-storm/518182.article [Accessed 25 August 2020]. While some broilers are unable to reach food and water points and die from starvation or dehydration, others die from heart attacks or lung problems brought on by their rapid growth.
How many meat chickens are there in the UK?
With almost 190 million alive at any one time, chickens reared for meat in the UK out-number all other land-based farmed animals combined by more than four to one. Poultry farming is by far the largest food sector in Britain, with over one billion broilers killed annually2Department for Environment, Food and Rural Affairs (Defra), 2020. Agriculture in the United Kingdom. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/895106/AUK-2019-25jun20.pdf [Accessed 17 July 2020]. – a number that’s steadily rising due to the popularity of chicken meat as a ‘healthier’ and more ‘environmentally-friendly’ alternative to red meat.3Salazar, E., Billing, S. and Breen, M., 2020. ‘We Need to Talk About Chicken’. Eating Better Report February. Available at https://www.eating-better.org/uploads/Documents/2020/EB_WeNeedToTalkAboutChicken_Feb20_A4_Final.pdf [Accessed 27 May].
In 2017, poultry overtook red meat sales the first time and now accounts for over 50 per cent of meat consumption.3Salazar, E., Billing, S. and Breen, M., 2020. ‘We Need to Talk About Chicken’. Eating Better Report February. Available at https://www.eating-better.org/uploads/Documents/2020/EB_WeNeedToTalkAboutChicken_Feb20_A4_Final.pdf [Accessed 27 May]. On average, people in the UK eat 35kg of poultry per year or over 400 chicken dinners.4Countryside Online, 2020. ‘All you need to know about the British poultry industry’. Countryside 6 April. Available at https://www.countrysideonline.co.uk/food-and-farming/feeding-the-nation/poultry/ [Accessed 27 May 2020]. More than 95 per cent of these chickens are intensively reared indoors with free range production systems accounting for less than four per cent of the total market and organic just one per cent.5Griffiths, R., 2017. ‘In Praise of Free-Range’. British Poultry Council 25 February. Available at https://www.britishpoultry.org.uk/introduction-to-marketing-standards-for-free-range-and-organic-poultry-meat/ [Accessed 27 May 2020].
What is the UK meat chicken industry worth?
According to the National Farmers’ Union chief poultry adviser, Gary Ford: “The UK slaughters 20 million broilers a week and the total value of the sector is growing by about three per cent a year.”6Riley, J., 2019. ‘Is now the right time to go into poultry farming?’ Farmers Weekly 24 May. Available at https://www.fwi.co.uk/livestock/poultry/is-now-the-right-time-to-go-into-poultry-farming [Accessed 13 May 2020]. It contributes more than £4.6 billion (GBP) to the economy every year and directly employs over 37,000 people.7British Poultry Council, 2020. ‘British Poultry Meat in the UK’. British Poultry Council. Available at https://www.britishpoultry.org.uk/about-bpc/ [Accessed 27 May 2020].
The UK is the third-largest overall chicken meat producer in Europe, with 2 Sisters Food Group heading the supply chain. They’re closely followed by Moy Park and Avara Foods (a joint Faccenda Foods and Cargill venture). As the largest of all chicken meat producers, 2 Sisters Food Group processes nine million birds a week across Europe and employs more than 20,000 staff.82 Sisters Food Group. Fast Facts. Available at: https://www.2sfg.com/about-us/fast-facts/ [Accessed 25 August 2020].
Like chickens destined for the egg-laying industry, broilers begin life as an incubated egg. These eggs are the product of genetically improved ‘parent stock’ – a separate breeding flock used to produce viable eggs. The eggs are stored and hatched on tiered racks in vast numbers.
Under optimal atmospheric conditions, with highly regulated temperatures and carbon dioxide concentrations, the chicks hatch after approximately 21 days.9Van Roovert-Reijrink, I., 2013. ‘Incubation affects chick quality’. Poultry World 14 May. Available at https://www.poultryworld.net/Genetics/Articles/2013/5/Incubation-affects-chick-quality-1183725W/ [Accessed 28 May 2020]. To reduce high levels of bacteria, formaldehyde or chlorine gas (which is known to be toxic to humans even at low densities) is used to sanitise the shell surface.10Maharjan, P., Cox, S., Gadde, U., Clark, F. D., Bramwell, K. and Watkins, S. E., 2017. ‘Evaluation of chlorine dioxide-based product as a hatchery sanitizer’. Poultry Science 96 (3). Available at https://www.sciencedirect.com/science/article/pii/S0032579119311411?via%3Dihub [Accessed 28 May 2020].
Naturally, mother hens would help their young break free of their shells but in the commercial industry, chicks have only their egg tooth to aid hatching. Once hatched, the chicks are vaccinated through misting or an injection on the back of the neck to protect them against diseases such as Newcastle disease virus, infectious bronchitis virus and Maerk’s disease.11European Food Safety Authority (EFSA), 2010. ‘Scientific Opinion on welfare aspects of the management and housing of the grand-parent and parent stocks raised and kept for breeding purposes’. EFSA Journal 8 (7): 1667. Available at https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2010.1667 [Accessed 28 May 2020].
Although some systems sex the birds, most don’t as both male and female chicks are used in broiler production.
Birds used to breed broiler chicks are called broiler breeders or parent stock. In the UK there are around eight million broiler breeders bred by the industry each year12Agriculture and Horticulture Development Board (AHDB), 2018. Poultry Pocketbook – 2018. Available at https://pork.ahdb.org.uk/media/275384/poultry-pocketbook-2018.pdf [Accessed 17 July 2020]. and each of these produce up to 140 chicks in their artificially short lifetime.13European Coalition for Farm Animals (ECFA), 2005. The Welfare of Broiler Chickens in the European Union – A Report by Compassion in World Farming Trust. Available at https://www.ciwf.org.uk/media/3818904/welfare-of-broilers-in-the-eu.pdf [Accessed 17 July 2020].
Usually reared in deep litter sheds with carefully managed lighting, temperature and ventilation, broiler breeders are sub-divided into pens containing around 1,000 birds each. Stocking densities are therefore not as high as those in regular broiler sheds, at approximately 25 kg of birds per square metre.
Weight control is used during the laying period to restrict growth and achieve desired levels of fertility. Unlike their offspring, who reach adult weights at around six weeks old, parent stock grow much more slowly and reach sexual maturity between 16 and 21 weeks old.
Restrictions in feed lead to their own welfare problems. Hunger causes the birds psychological stress, resulting in increased incidence of abnormal behaviours such as feather-pecking and greater levels of aggression around feeding time.14Mench, J. A., 2002. ‘Broiler breeders: feed restriction and welfare’. World’s Poultry Science Journal 58 (1) March pp 23-29. They often drink more as well, which leads to wetter, poorer litter and subsequent skin (dermatitis) lesions or hock burns.15Farm Animal Welfare Council (FAWC), 1998. Report on the welfare of broiler breeders. FAWC. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/325543/FAWC_report_on_the_welfare_of_broiler_breeders.pdf [Accessed 3 June 2020].
Around 50 per cent of the breeding flock are male, in order to achieve the maximum number of fertile hatching eggs.16Farmers Weekly, 2013. ‘Getting the most from broiler breeders’. Farmers Weekly 22 January. Available at https://www.fwi.co.uk/livestock/poultry/getting-the-most-from-broiler-breeders [Accessed 17 July 2020]. Males are typically kept apart from females until at least six weeks of age and suffer from painful mutilations such as dubbing, despurring and declawing (see injury and mutilation section), in an effort to minimise some of the abnormal behaviours and consequences of living in highly unnatural and artificial environments.
Unlike laying hens, which are nearly all brown, broilers typically have white feathers and since the 1950’s have been bred to grow four times faster than laying hens.17European Commission. 2016. Report from the commission to the European parliament and the council on the impact of genetic selection on the welfare of chickens kept for meat production. Available at: https://ec.europa.eu/transparency/regdoc/rep/1/2016/EN/1-2016-182-EN-F1-1.PDF [Accessed 25 August 2020]. As a result, modern broilers take an average 35-45 days to reach target slaughter weights of around two and a half kilograms.18Colley, C. and Wasley, A., 2020. ‘Industrial-sized pig and chicken farming continuing to rise in UK’. The Guardian 7 April. Availalble at https://www.theguardian.com/environment/2020/apr/07/industrial-sized-pig-and-chicken-farming-continuing-to-rise-in-uk#maincontent [Accessed 27 May 2020].
The most-commonly bred chicken for meat worldwide, is the Ross breed. Other fast-growing breeds include the Arbor Acre, Cobb and Marshall.
Intensive chicken farms are those with the capacity to house at least 40,000 birds and as such require a permit from the Environment Agency to operate. From 2011 to 2015, the poultry sector saw a 27 per cent leap in the number of farms housing more than 40,000 birds.19Wasley, A., 2018. ‘Chicken mega-farms are how we’ll feed the UK, says poultry industry head’. The Guardian 3 July. Available at https://www.theguardian.com/environment/2018/jul/03/intensive-chicken-mega-farms-feed-uk-poultry-industry-head-richard-griffiths [Accessed 27 May 2020].
In 2017, the number of large intensive farms – pig and poultry – with an Environment Agency permit in the UK in stood at 1,674 – an increase of 26 per cent since 2011 when there were 1,332 facilities requiring a permit – and poultry farms accounted for 86 per cent of the total.19Wasley, A., 2018. ‘Chicken mega-farms are how we’ll feed the UK, says poultry industry head’. The Guardian 3 July. Available at https://www.theguardian.com/environment/2018/jul/03/intensive-chicken-mega-farms-feed-uk-poultry-industry-head-richard-griffiths [Accessed 27 May 2020].
Over 95 per cent of chickens raised for meat in the UK are housed in intensive units5Griffiths, R., 2017. ‘In Praise of Free-Range’. British Poultry Council 25 February. Available at https://www.britishpoultry.org.uk/introduction-to-marketing-standards-for-free-range-and-organic-poultry-meat/ [Accessed 27 May 2020]. – giant sheds with carefully monitored environments to encourage growth. For the first week of their lives, broiler chicks are subjected to constant lighting and require temperatures of 33° C.6Riley, J., 2019. ‘Is now the right time to go into poultry farming?’ Farmers Weekly 24 May. Available at https://www.fwi.co.uk/livestock/poultry/is-now-the-right-time-to-go-into-poultry-farming [Accessed 13 May 2020]. After that, sheds are supposed to provide a period of four continuous hours of darkness as per the EU directive 2007/43/EN.20European Union, 2007. ‘Laying down minimum rules for the protection of chickens kept for meat production’. Official Journal of the European Union. Available at https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32007L0043&from=EN [Accessed 28 May 2020].
In the UK, broiler sheds are not required by law to be built with windows and can rely on artificial lighting to stimulate activity but in 2018, Red Tractor announced new regulations making windows compulsory and gave its scheme members two and a half years to comply.21Ryan, C., 2018. ‘Windows made compulsory in chicken sheds in updated Red Tractor standards’. Poultry News 4 April. Available at http://www.poultrynews.co.uk/production/broiler-production/windows-made-compulsory-in-chicken-sheds-in-updated-red-tractor-standards.html [Accessed 4 June 2020]. As well as being evenly distributed to provide uniform daylight throughout the building, the transparent area of the windows must equate to three per cent of the floor area, provide adequate insulation and prevent condensation.6Riley, J., 2019. ‘Is now the right time to go into poultry farming?’ Farmers Weekly 24 May. Available at https://www.fwi.co.uk/livestock/poultry/is-now-the-right-time-to-go-into-poultry-farming [Accessed 13 May 2020].
Automated feed lines with circular pan or track feeders line the sheds and are carefully managed and designed to fatten the birds quickly. Water access is limited to nipple drinkers or less common bell drinkers and may be treated with peroxide or chlorine to try and limit bacterial infections. These treatments are generally removed five to seven days prior to slaughter in an effort to prevent them from entering the food chain.
As per the Department for Environment, Food and Rural Affairs’ (Defra) Code of Practice for the welfare of meat chickens and meat breeding chickens (2018), the distance any bird should have to travel in a house to reach feed should not be more than four metres and not more than three metres for water. Although water should be provided up to the start of the catching procedure for transportation to slaughter, food can be withheld for up to 12 hours.22Department for Environment, Food and Rural Affairs (Defra), 2018a. Code of practice for the welfare of meat chickens and meat breeding chickens. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/694013/meat-chicken-code-march2018.pdf [Accessed 4 June 2020].
Litter, composed of straw, wood shavings, peat or paper, is laid to absorb broiler waste and is not usually cleaned or changed during their entire lifetime. With tens of thousands of birds sharing the same space, the litter can become wet very quickly. By sitting in their own waste broilers are prone to suffer from contact dermatitis, where the skin is chemically burned and eventually turns black.18Colley, C. and Wasley, A., 2020. ‘Industrial-sized pig and chicken farming continuing to rise in UK’. The Guardian 7 April. Availalble at https://www.theguardian.com/environment/2020/apr/07/industrial-sized-pig-and-chicken-farming-continuing-to-rise-in-uk#maincontent [Accessed 27 May 2020].
Researchers at the University of Cambridge found that these ‘hock burns’ could be identified in 82 per cent of chickens sold in supermarkets but said the figure could be even higher as these lesions are sometimes removed prior to the meat going on sale.23Broom, D. M. and Reefmann, N., 2005. ‘Chicken welfare as indicated by lesions on carcases in supermarkets’. British Poultry Science 46(4):407‐414. Although more recent figures on hock burn incidences are difficult to find, a 2016 investigation suggests that one in three supermarket chickens still suffer from skin burns24Sommerlad, N., 2016. ‘Supermarket chickens are being kept in their own excrement, shock investigation claims’. Mirror Online 19 September. Available at https://www.mirror.co.uk/news/uk-news/supermarket-chickens-being-kept-excrement-8871496 [Accessed 4 June 2020]. and in 2020, The Guardian reported that one in ten KFC chickens also suffer hock burn caused by ammonia.25Levitt, T., 2020. ‘KFC admits a third of its chickens suffer painful inflammation’. The Guardian Thursday 30 July. Available at https://www.theguardian.com/environment/2020/jul/30/kfc-admits-a-third-of-its-chickens-suffer-painful-inflammation [Accessed 3 August 2020].
Additional straw bales to lay as top litter during a cycle can be stored inside the sheds and are counted as a form of enrichment, which supposedly provides birds with ‘more choice in [their] activities’ and improves their health and welfare.’22Department for Environment, Food and Rural Affairs (Defra), 2018a. Code of practice for the welfare of meat chickens and meat breeding chickens. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/694013/meat-chicken-code-march2018.pdf [Accessed 4 June 2020].
Other forms of environmental enrichment include perches, low barriers and pecking objects such as traffic cones, empty containers and brassicas. There are no legal requirements as to how many pecking objects should be provided per thousand birds but initiatives like the Better Chicken Commitment call for at least two metres of usable perch space and two pecking substrates per 1,000 birds.26Davies, J., 2020. ‘What the Better Chicken Commitment means for farmers’. Farmers Weekly 8 February. Available at https://www.fwi.co.uk/livestock/poultry/broilers/what-the-better-chicken-commitment-means-for-farmers [Accessed 17 July 2020].
In some cases, flocks are ‘thinned’ as they get closer to their final slaughter weights in order to create more space for the remainder of the birds. According to the British Poultry Council, usually 25-30 per cent of birds (often female) are removed from the shed to be killed for markets that desire smaller birds, and the remainder are left to grow on.27British Poultry Council, 2020. ‘Thinning’. British Poultry Council. Available at: https://www.britishpoultry.org.uk/glossary/thinning/ [Accessed 27 May 2020]. Bio-security is often broken during thinning and it increases stress levels in the units, which often leads to higher levels of disease outbreak.28Allen, V. M., Weaver, H., Ridley, A. M., Harris, J. A., Sharma, M., Emery, J., Sparks, N., Lewis, M. and Edge, S., 2008. ‘Sources and spread of thermophilic Campylobacter spp. during partial depopulation of broiler chicken flocks’. Journal of Food Protection 71: 264-270.
Free-range and organic
Both free-range and organic production systems adhere to conditions outlined by the EU Regulations 543/2008 (free-range) and 889/2008 (organic).20European Union, 2007. ‘Laying down minimum rules for the protection of chickens kept for meat production’. Official Journal of the European Union. Available at https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32007L0043&from=EN [Accessed 28 May 2020].
Extensive indoor, free-range and traditional free-range are all marketing terms for slower growing breeds of birds, such as the JA757, reared for around 56 days (as opposed to the standard 42) with fewer birds permitted per square metre of indoor space. They also have daytime access to open-air runs for a fixed period during their lives.
Organic broilers have it a little easier than free-range birds with daily access to the outdoors for at least a third of their lives and are reared to a lower stocking density over a longer period of time.5Griffiths, R., 2017. ‘In Praise of Free-Range’. British Poultry Council 25 February. Available at https://www.britishpoultry.org.uk/introduction-to-marketing-standards-for-free-range-and-organic-poultry-meat/ [Accessed 27 May 2020]. However, both free-range and organic birds spend most of their lives indoors and they are killed from just two months old.
Injury and mutilation
Lameness is a common occurrence on broiler farms as a result of selective breeding. The birds’ rapid weight gain leads to developmental abnormalities in their bones and joints, which are exacerbated by stress and infections caused by bacteria such as Enterococcus caecorum and Staphylococcis aureus.
Almost one-third of intensively reared broiler chickens in the UK develop heart and lung problems and more than half of the birds in flocks with fast-growing breeds have severe walking problems.18Colley, C. and Wasley, A., 2020. ‘Industrial-sized pig and chicken farming continuing to rise in UK’. The Guardian 7 April. Available at https://www.theguardian.com/environment/2020/apr/07/industrial-sized-pig-and-chicken-farming-continuing-to-rise-in-uk#maincontent [Accessed 27 May 2020]. These leg disorders have been identified by the European Commission’s Scientific Committee on Animal Health and Animal Welfare (SCAHAW) as ‘a major cause of poor welfare in broilers’ and likely cause chronic pain.29Science Committee on Animal Health and Animal Welfare (SCAHAW), 2000. ‘The Welfare of Chickens Kept for Meat Production (Broilers)’. Report of the Scientific Committee on Animal Health and Animal Welfare. Available at https://ec.europa.eu/food/sites/food/files/animals/docs/aw_arch_2005_broilers_scientific_opinion_en.pdf [Accessed 4 June 2020].
Other injuries broilers suffer are a result of feather-pecking and cannibalism. These behavioural issues often develop when the chicks are just a few weeks old and can become a habit that spreads through the flock. Once stressed, young broilers begin picking the feathers, combs, toes or vents of other birds.
Once a wound has opened, the blood drives cannibalistic behaviour. Yet despite knowing that environmental enrichment significantly lessens feather-pecking, there are no legal requirements to provide it.
Unlike egg-layers, broilers in Britain are not typically beak-trimmed as they’re normally slaughtered before reaching sexual maturity.22Department for Environment, Food and Rural Affairs (Defra), 2018a. Code of practice for the welfare of meat chickens and meat breeding chickens. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/694013/meat-chicken-code-march2018.pdf [Accessed 4 June 2020]. In an effort to prevent aggression in breeding (parent stock) birds, who do reach sexual maturity, it’s generally only the males that have their beaks trimmed. The process is carried out at around five days of age and can lead to severe and lasting pain.30Haslam, S., 2011. ‘Broiler chickens’. Management and Welfare of Farm Animals: The UFAW Farm Handbook. Chichester: Wiley-Blackwell.
The removal of all or part of the comb (dubbing), the removal of the spur bud on the back of the leg (despurring) and the removal of the dew and pivot claw from the feet (declawing) are all other mutilations that may be carried out on male broiler-breeders. Dubbing supposedly helps to limit sexing errors during rearing and helps avoid loses due to excessive comb growth, whereas despurring and declawing reduces damage to female birds during mating.15Farm Animal Welfare Council (FAWC), 1998. Report on the welfare of broiler breeders. FAWC. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/325543/FAWC_report_on_the_welfare_of_broiler_breeders.pdf [Accessed 3 June 2020].31Department for Environment, Food and Rural Affairs (Defra), 2019. Guidance Broiler (meat) chickens: welfare recommendations. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf [Accessed 4 June 2020].
Infectious diseases can run rampant on intensive farms – which provide the perfect ‘petri dish’ for rapid spread. An outbreak of Campylobacter, for instance, can infect most chickens in a shed of 30,000 within 72 hours to one week.32Ramabu, S., Boxall, N., Madie, P. and Fenwick, S., 2004. ‘Some potential sources for transmission of Campylobacter jejuni to broiler chickens’. Letters in Applied Microbiology 39 pp. 252-256. It is often spread from shed to shed during the thinning stage (where some birds are removed to prevent further overcrowding and for certain markets that favour smaller chickens for human consumption) due to poor biosecurity measures in place on the farm.
Campylobacter is a pathogenic (disease causing) bacterium that can infect humans and is the most common form of food poisoning in the UK. According to Defra, cases increased in 2017 after a decline over the previous two years and are associated with the consumption of chicken or duck liver parfait or paté.33Department for Environment, Food and Rural Affairs (Defra), 2018b. Zoonoses Report UK 2017. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/765111/UK_Zoonoses_report_2017.pdf [Accessed 17 July 2020].
In the UK and abroad, E. coli and Salmonella enteritidis are other well-known dangerous food-borne bacteria that when ingested can lead to serious food poisoning. Symptoms include diarrhoea, vomiting, nausea, fever and abdominal pain.
A classic example of a zoonotic disease, avian influenza or bird flu is caused by the H5N1 virus and has been infecting poultry and other land-birds since the 1950s but in 1996 a highly pathogenic strain of H5N1 killed more than 40 per cent of the birds it infected. The virus has become more deadly directly due to factory farming – the intensely overcrowded conditions enable the virus to mutate and spread. Commercial poultry farms, wet markets, poultry slaughtering facilities, pig farms, human dietary habits and the global trade in exotic animals are all implicated in the spread of influenza viruses.
There are currently at least three strains of bird flu that can infect humans – H5N1, H7N9 and H9N2. H5N1 is a virus concerning many scientists as the mortality rate in humans is a terrifying 60 per cent34World Health Organization, 2020. Influenza. World Health Organization. Available https://www.who.int/influenza/human_animal_interface/avian_influenza/h5n1_research/faqs/en/ [Accessed 25 August 2020]. – by contrast, seasonal flu kills about 0.1 per cent of those infected. Globally, more than 15,000 outbreaks of infection with H5N1 were reported in domestic birds such as chickens, ducks, turkeys and geese between 2005 and 2018.35Chowdhury, S., Hossain, M.E., Ghosh, P.K. et al. 2019. The Pattern of Highly Pathogenic Avian Influenza H5N1 Outbreaks in South Asia. Trop Med Infect Dis. 2019;4(4):138. Available at https://pubmed.ncbi.nlm.nih.gov/31783701/ [Accessed 25 August 2020]. Most cases of infection in humans have involved individuals handling, slaughtering or consuming infected poultry and as of December 2006, more than 240 million poultry either died or were slaughtered to prevent the spread of this virus.35Chowdhury, S., Hossain, M.E., Ghosh, P.K. et al. 2019. The Pattern of Highly Pathogenic Avian Influenza H5N1 Outbreaks in South Asia. Trop Med Infect Dis. 2019;4(4):138. Available at https://pubmed.ncbi.nlm.nih.gov/31783701/ [Accessed 25 August 2020].
Since 2003, over 800 people have been infected with the H5N1 avian influenza viruses and over 450 have died, with fatalities in Indonesia, Egypt, Vietnam, China, Cambodia, Thailand and Canada. These numbers might seem low, compared with other pandemics, however, if the virus changes to become more easily spread between humans, we could be facing a deadly pandemic the likes of which we have never seen before.
There are a number of assurance schemes for broilers, including Red Tractor, The Soil Association and RSPCA Assured. The UK standard allows for 39kg (between 14-15 birds at adult weight) per square metre. Red Tractor and RSPCA Assured allows for 38kg (14 birds at adult weight) per square metre and 30kg (around 11 birds at adult weight) per square metre respectively.
About 90 per cent of birds are produced to Red Tractor standards as most retailers insist upon this as a minimum. When buying chicken, consumers seem more reluctant to pay for higher welfare chickens and ‘RSPCA Freedom Food [now RSPCA Assured] birds account for just three per cent of the market. Sales of Freedom Food chicken have not seen year-on-year growth’ (Riley, 2019).
Better Chicken Commitment
Since November 2016, the Better Chicken Commitment (BCC) has been growing in momentum across the world. Over 170 leading food companies have publicly committed to improving welfare practices for chickens that stipulate a change in breed type, stocking densities and lighting levels, among other standards.
An initiative involving a coalition of European animal welfare groups, including the RSPCA and Compassion in World Farming, the commitment promotes phasing out breeds such as the Ross 308 for slower-growing Ranger golds in order to improve the lives and health of chickens bred for meat.
Although the improvements outlined by the BCC have not been incorporated into law, the coalition is calling for retailers and food outlets to pledge to source chicken only from producers applying the higher welfare standards by 2026 (Davies, 2020). Its biggest road block in achieving that goal, however, is the 33p per bird increase in rearing costs and the 22 per cent extra land required to produce a tonne of BCC poultry meat compared with intensively farmed, fast-growing birds (Davies, 2020).
However, the conditions proposed by BCC are still grossly unnatural, and chickens all end up at the slaughterhouse at a mere fraction of their natural lives.
In the UK, we now kill more than one billion broiler chickens annually, or roughly three million birds a day.1Department for Environment, Food and Rural Affairs (Defra), 2020. Agriculture in the United Kingdom. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/895106/AUK-2019-25jun20.pdf [Accessed 17 July 2020]. As with poultry farming, slaughter is big business and as with any business, time is money – which means the slaughter lines prioritise speed over welfare. Broiler chickens are killed at just six to seven weeks old; a chicken’s natural lifespan is five to eight years and some live 10 to 12 years.
Catching and depopulation
To maintain a high profit margin, it is common practice in poultry farming to overstock sheds. This not only allows for a high mortality rate but also provides for the thinning of flocks for markets that, for one reason or another, prefer smaller birds. The British Poultry Council claim that the average mortality rate for the industry as a whole is two to three per cent (22 to 34 million birds a year) but the UK’s Red Tractor farm assurance scheme requires mortality to not exceed 5 per cent.2Levitt, T., 2020. ‘KFC admits a third of its chickens suffer painful inflammation’. The Guardian Thursday 30 July. Available at https://www.theguardian.com/environment/2020/jul/30/kfc-admits-a-third-of-its-chickens-suffer-painful-inflammation [Accessed 3 August 2020].
In a practice called ‘thinning’, between three to six thousand birds are removed from a shed, allowing those that remain more room to grow. It involves rearing the birds to the maximum permitted stocking density before removing a proportion of them, often by hand at around four to five weeks of age. As it’s linked to higher campylobacter rates by the European Food Safety Authority, the RSPCA Assured scheme banned it in 2016.3Perkins, C., 2015. ‘RSPCA bans chicken flock thinning to improve welfare and cut campylobacter’. The Grocer 23 November. Available at https://www.thegrocer.co.uk/meat/rspca-bans-chicken-flock-thinning-to-improve-welfare/528057.article [Accessed 17 August 2020].
However, thinning is common practice in intensive poultry systems because it allows farmers to maximise space for rearing birds while meeting necessary requirements for stocking densities and market demand for different sizes of birds.
When thinning and depopulating the shed, lighting is kept low to minimise panic amongst the birds. Workers catch birds by their legs and cram them into crates, while forklifts drive back and forth carrying full crates to transport trucks.
According to government guidelines, no catcher should carry by the legs more than three chickens in each hand (or two adult breeding birds) and should never carry birds by their heads, necks, tails or wings (Defra, 2019a).
Government guidelines also indicate that birds ’should not be deprived of feed or water before transport’ but feed and watering lines are often raised to allow catchers and forklift drivers better access to the sheds. Prior to slaughter, feed can be withheld for up to 12 hours, but not water.4Department for Environment, Food and Rural Affairs (Defra), 2019a. Guidance Broiler (meat) chickens: welfare recommendations. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf [Accessed 17 July 2020].
Once the birds are loaded into crates to be transported to the slaughterhouse, the government’s guidelines are extremely vague, stating only that ’during the time birds are held in the containers prior to and after transport they should be protected from bad weather and excessively hot or cold conditions’.4Department for Environment, Food and Rural Affairs (Defra), 2019a. Guidance Broiler (meat) chickens: welfare recommendations. Defra. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/732227/code-of-practice-welfare-of-laying-hens-pullets.pdf [Accessed 17 July 2020]. However, as the sides of transport trucks are usually open, birds are subjected to weather extremes in both summer and winter months, with no additional provisions in place.
There are also no definitive time limits on transportation in the Welfare of Animals (Slaughter or Killing) Regulations, it merely suggests that animals should be unloaded as soon as possible after arrival at a slaughterhouse.5Gov.uk, 1995. The Welfare of Animals (Slaughter or Killing) Regulations 1995. Available at https://www.legislation.gov.uk/uksi/1995/731/contents/made [Accessed 25 August 2020]. It is more likely that producers’ interpretations of the legislation will be informed more by commercial priority than animal welfare.
Chickens killed for meat are slaughtered in two ways – either by controlled atmosphere systems (gassing) or electrical stunning and throat cutting. In 2018, the Food Standards Agency reported in their slaughter methods survey that gas killing accounted for 70 per cent of all poultry, indicating that gas systems have now become the main slaughter method for chickens.6Department for Environment, Food and Rural Affairs (Defra), 2019b. Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf [Accessed 17 July 2020].
To gas kill chickens, birds remain in the crates in which they were transported and are placed into a chamber. They are then exposed to mixtures of air and gas until dead. It’s generally considered to have welfare advantages over electrical stunning and throat cutting because it bypasses the live shackling stage. Gas killing birds is not a method that can be used for religious slaughter, as animals must be alive when their throats are cut.
Inhalation of carbon dioxide can cause distress, which leads the birds to gasp and shake their heads, so it may only be used under special license from Defra. Argon gas is undetectable to chickens and is believed to be less stressful for the birds but it is the most expensive of the gases and can lead to skin hemorrhaging.
Electrical stunning and throat cutting involves hanging live birds upside down by their legs on metal shackles and moving them along a conveyor belt towards an electrified water bath. When the bird’s head touches the water, an electrical circuit between the water bath and shackle stuns the birds before they move along the line to a mechanical neck cutter that severs the major blood vessels in their necks.
The high throughput in slaughterhouses – which have line speeds up to 10,000 birds an hour – leads to considerable welfare concerns. Some birds, who lift their heads away from the water baths, miss being stunned entirely and have their throats cut while still fully conscious. The neck cutter is also fallible, as some birds have been found to receive only single cuts while others are missed entirely. In these instances, birds may be fully or partially conscious when they enter the scalding tanks to loosen their feathers and are essentially boiled alive.
The explosion of broiler production worldwide is a disaster for both chickens and consumers. Growing levels of obesity, dwindling feed stocks, food poisoning and the ever-looming threat of a global pandemic – as well as the staggering scale of appalling suffering involved in poultry farming – makes it crystal clear that the solution to all these problems is to choose vegan.