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Broiler chickens reared for meat are crammed together, many thousands of birds in each barren shed. They are not caged, but kept at such high stocking densities that the birds quickly carpet the floor of the shed.
Broiler chickens grow at super-fast rates, so fast that their bones, heart and lungs often cannot keep pace. About a quarter of European broiler chickens under 6 weeks old suffer painful crippling due to fast growth rates, whilst one in a hundred of these very young birds dies of heart failure.
UK Government guidelines set a maximum stocking density for broiler chickens. Whilst set too low, it is hoped that future EU legislation will alleviate the immense suffering prevalent in broiler rearing.

There is no specific EU legislation on keeping and breeding poultry for meat production. Following pressure from animal welfarists, this omission is now recognised.

Evidence of Suffering

Poultry meat is most commonly produced from “broiler” chickens. These are the large, dumpy, white birds now sold the world over. There are about 20 billion broiler chickens worldwide at any one time. About a quarter are found in the USA, nearly a fifth in China, and a seventh of the world total in the European Union.

Standard practice for factory rearing of broiler chickens is to cram them in their thousands into windowless sheds. In Europe, the largest sheds can contain up to 100,000 birds each, but 10,000-40,000 is the norm. Broiler chickens are not usually reared in cages, but are kept on a litter-covered floor.

The birds are put into the sheds as day-old chicks. They are forced to grow quickly, and within weeks, one can barely see the floor, so thickly is it covered with chickens. Stocking densities vary between 15 and 23 birds per square metre. This equates to each bird being allocated about as much space as on the cover of a standard telephone directory.

Modern broiler chickens are ready for slaughter at 6-7 weeks old. They are now growing twice as fast as they did 40 years ago. This fast growth is due to selective breeding for fast-growing strains, and feeding them on high protein diets that often contain growth-promoting antibiotics.

Fast growing broiler chickens suffer high rates of lameness, heart disease and skin sores. Although broilers now put on weight very quickly, the strength of young bones has not changed significantly. Putting on weight at twice their normal rate has led to the travesty of a 42-day old bird’s skeleton being forced to carry the weight of an 84-day old. This often causes lameness and painful crippling.

Broilers are also growing too fast for their heart and lungs. Heart failure is a common problem amongst broiler chickens, caused by a lack of oxygen supply to the overweight birds’ bodies, making their hearts work abnormally hard.

There are two major conditions accounting for significant mortalities within the broiler industry; ascites and sudden death syndrome (SDS). European Commission veterinary advisors concluded that both ascites and SDS pose serious welfare problems, and blamed these on fast growth rates. In the UK alone, heart failure kills an estimated 17,000 baby broiler chickens a day.

As broiler chickens grow, they tend to become increasingly inactive. This is due to overcrowding as they take up space in their overstocked shed, and because their overweight bodies make activity more difficult. With little room to move and often wracked with painful deformities, broilers spend a lot of time squatting on the litter floor. This puts them at risk of developing sores or ammonia burns from the faeces-covered litter. These burns can cause breast blisters, hock burns, and ulcerated feet, all painful conditions that are common in broilers.

The EU Requests Scientific Opinion

The EU Commission has asked its Scientific Committee on Animal Health and Animal Welfare to prepare a report on the welfare of chickens bred for meat production. The Commission asked that particular attention be paid to problems arising from genetic selection for increased appetite, the space requirement for birds during the fattening period and health problems arising from rapid fattening.2

Existing UK legislation and Codes protect broiler parent stock to a limited degree (please see section on feed restriction). Only Sweden and Switzerland exercise specific regulations for young broilers, i.e. those destined for slaughter at around six weeks. Germany and the UK have official recommendations (Codes of Practice) but most other countries rely on advice from breeding companies for their practices.3

In Sweden, companies may keep their birds at a maximum stocking density (of 36kg/m2) only if conditions are deemed optimum by the relevant authorities; the lower limit is 20 birds /m2. Swedish law also demands a minimum period of two hours of darkness out of the 24. In Switzerland the law fixes an upper limit of 30kg/m2 for stocking density and requires that birds be given at least eight hours of darkness, when kept in windowless sheds.4

Genetic selection for fast growth

Many of the diseases now plaguing the broiler industry are the result of genetic selection for fast growth: “Increasing breast muscle yield has caused broilers’ centre of gravity to move forward and breasts to be broader. These changes have implications for walking ability, gait and mechanical stresses on legs and hip joints. Accelerated skeletal growth has led to an increased incidence of bone disorders, most resulting from growth plate pathologies. Stocks in which rapid growth is combined with low FCR (food conversion rate) typically show an increased disposition to low thyroid hormone concentrations, low metabolic rate, hypertrophy of the right ventricle of the heart and Ascites (Scheele, 1997). These pathologies can be attributed to an insufficient oxygen supply in metabolism, due to genetically (and environmentally) induced mismatches between energy-supplying and energy-consuming organs. The same endocrine factors which exert a major influence on growth are also important regulators of immune development and function (Marsh 1995) and concern has
been expressed about possible increased susceptibility to viral and bacterial infection (Urrutia, 1997).”5

UK’s Farm Animal Welfare Council* demands progress

In a letter dated 25th October 2000 Mrs. Judy MacArthur Clark, chairman of the Farm Animal Welfare council wrote to Mr. Elliot Morley, the Minister responsible for animal welfare: “...the continuing uncertainty (regarding data on the severity of leg
problems in broilers - Ed.) highlights the urgent need for a definitive study on the current state of leg health in UK broiler production... we believe there is a need to change the current perception of, and response to, broiler leg problems within the
welfare enforcement framework. Application of welfare codes should be rigorously pursued through inspections, and existing legislation should be effectively enforced on farms, in transport and at slaughterhouses. This might encourage poultry producers to slaughter birds a few days earlier (at a lighter weight) which could markedly reduce the occurrence of leg health problems. Retailers must also be made fully aware of the welfare implications of their demand for birds at the current marketed weights and encouraged to seek the benefits they could claim from providing customers with slightly lighter/younger birds... In conclusion, I can only reinforce the concern first expressed in 1992 over the real welfare challenge of lameness in broilers.”

*The Farm Animal Welfare Council is an independent body, set up in 1979, to keep under review the welfare of farm animals and to advise Agriculture Ministers on any legislative (or other) changes that may be necessary.

The future

Welfarists anticipate that EU-wide legislation regulating the broiler chicken industry will be on the statute books in the near future. This legislation must be based on the birds’ needs.

The industry’s quest for heavy, meaty progeny from light, agile and desperately hungry parent stock has posed seemingly insoluble welfare problems. Nothing short of a programme of radical reform will solve the man-made problems inherent in
today’s broiler industry.


Report of the Scientific Committee on Animal Health and Animal Welfare: “The Welfare of Chickens Kept for Meat Production (Broilers)”, March 2000.






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