| Broiler
chickens (often referred to as ‘Broilers’) have been
selectively bred and reared for their meat rather than eggs. The
industry began in the late 1950’s and there are approximately
116 million broilers in the UK at any one time. Over 800 million
broiler chickens were slaughtered in the UK in 2006(1).
The majority of broiler chickens are housed in large windowless
sheds in massive flocks holding tens of thousands of birds (20,000
- 50,000)(2).
Production & Welfare
Broilers are hatched from eggs laid by breeding stock (broiler breeders). Broiler
breeders are usually housed on deep litter (soft wood shavings, chopped
straw, etc). They are slaughtered at around 10 months old when their peak
egg production is past. Each broiler breeder produces up to 140 chicks.
While broiler breeders are growing to adulthood their food is severely
restricted, they therefore suffer severe hunger. The restriction of food
is carried out to prevent them from growing as fast as the meat broilers,
breeder broilers are required to survive to adulthood in order to produce
chicks(2). The surplus chicks produced (referred to as ‘hatchery
waste’) are killed by a number of permitted methods. These include
the use of mechanical apparatus producing immediate death, (such as a homogeniser
which minces up chicks alive), exposure to gas mixtures or dislocation
of the neck(1).
Intensively reared broilers exist on concrete-floored sheds are covered with
a layer of litter. Chicks are placed in a brooding area when they arrive in-house
and require careful monitoring as they are particularly susceptible to extremes
of temperature. Broilers should not be exposed to strong, direct sunlight or
hot humid conditions which could cause heat stress and lead to death. All accommodation
should be designed with adequate ventilation and access to light, either natural
or artificial. Lighting should allow the birds to see clearly and stimulate
activity. Houses should have a uniform level of light and if behavioural problems,
such as cannibalism, occurs then it recommended the lights are dimmed for a
few days. Artificial light should be given for at least 8 hours a day for those
with no access to daylight and 30 minutes of darkness must be given each day
so the birds become used to total darkness and help prevent panic in the event
of a power failure.
Birds are closely packed and have little space to move around in. The recommended
stocking density is stated as 34 kg of bird per square metre. This means each
bird has an area of around 0.05m², similar in size to an A4 sheet of paper.
As the birds grow, conditions deteriorate and the sheds become increasingly
crowded until the shed floor becomes a solid mass of chickens competing to
reach food and water. The birds’ natural behaviour to perch, walk, run
and fly are obviously frustrated in the shed environment.
Standard intensively farmed broiler chickens are reared to their slaughter
weight of around 1.8 to 3 kg within just 6 weeks of being hatched (chickens
are normally fully grown by 5-6 months). By selective breeding, the length
of time broiler chicks take to grow to 2 kg has been halved in the last 30
years. As broilers are bred to grow as fast as possible this has lead to them
becoming more inactive. Their frame cannot support their own weight and this
affects the way they walk and puts additional stresses on their hips and legs.
At just 6 weeks old, they spend 76%-86% of their time lying down(3).
Birds severely crippled and deformed die of starvation and thirst, unable to
reach food or water. Other birds may only be able to move by using their wings
to balance. The Farm Animal Welfare Council (FAWC) describes these birds as "obviously
distressed". Broilers have a mortality rate 7 times that of young laying
hens of the same age(2). Every day some 100,000 birds die in UK broiler
sheds as a result of heart failure, disease and afflictions caused by intensive
methods of production(4).
Mutilations of broilers can cause considerable pain and it is recommended by
DEFRA that they should only be carried out where necessary to avoid a worse
welfare problem. Beak-trimming of birds for meat should not be necessary as
they are usually slaughtered before reaching sexual maturity. If it is to be
carried out then it should be done by either a veterinary surgeon or in accordance
with the Veterinary Surgery (Exemptions) Order 1962. Dubbing (cutting out of
toes) must be performed by a vet if the bird has reached 3 days in age, otherwise
it may be carried out by unqualified persons over 18 using a suitable instrument.
Other mutilations broilers may have to endure include de-spurring, de-clawing
and toe removal. The following mutilations are prohibited by law; de-winging,
pinioning, notching, tendon severing, the use of blinkers which pierce the
nasal septum, surgical castration and devoicing(1).
Disease
The unnatural growth rate of broilers, together with the lack of space to move
or exercise, encourages the birds to rest on the litter. As broilers spend
their entire lives in direct contact with the bedding their health and welfare
are linked to its quality.(5). Conditions such as hock burn, breast
blisters, skeletal disorders, lameness and heart-failure are consequences of
management-related problems.
 Hock
burn & breast blisters
When caked litter accumulates the wet droppings on the surface cause inflammation
of the skin over the hock, (hocks are the joint in the hind legs). This may
lead to ulceration followed by scabs over the ulcers. Hock burn is extremely
painful for the bird and can often be seen on chickens sold in supermarkets.
Soiled litter can also affect the bird’s breast leading to blisters which
if they become infected leads to abscess formation. As these birds spend more
of their time sitting on the damp litter this ultimately accelerates the incidence
of leg weakness.
Skeletal
disorders & lameness
The two main disorders affecting broilers are due to their rapid growth rates.
Bone growth disorders affect young birds whilst arthritis is prevalent among
broiler breeders. In birds over around 35 days the structure supporting the
bird (bones, tendons and ligaments) often cannot keep pace with the growth
of muscle and fat(5). A DEFRA-funded study, conducted by a team of
independent researchers at Bristol University, showed that almost 30% of broilers
had moderate to severe leg disorders that impaired their ability to move. This
indicates that over 200 million broilers in the UK suffer from lameness, and
scientific research strongly suggests, this is painful for the birds. Some
of the chickens have difficulty reaching food/water and in the worst cases
they can barely move at all(6).
Heart
failure
Fast growing broilers suffer from 2 forms of heart disease, ascites and Sudden
Death Syndrome (SDS). These conditions are due likely to the fact that the
broilers’ require high oxygen levels to keep up with their metabolism
which in turn intensifies the activity of their cardio-pulmonary systems.
Keratocon-junctivitis
Chickens, like humans, are sensitive to ammonia. Prolonged exposure to high
levels (50 to 100 parts per million) can result in kerato-conjunctivitis,
this is a painful eye condition leading to blindness(7).
Bacterial
infections
The unhealthy, intensive nature of broiler farms means bacteria can spread
easily through flocks. Salmonella and Campylobacter are widespread in broiler
farms and frequent causes of food poisoning in humans.
Bird
Flu
Avian influenza is a highly contagious viral disease affecting the respiratory,
digestive and/or nervous system of many species of birds. It is caused by a
Type A influenza virus, a disease which must be notified to the local State
Veterinary Service Divisional Veterinary Manager. There are two types of avian
influenza virus, low pathogenic (LPAI) and highly pathogenic (HPAI). Within
the LPAI types there is evidence that certain H5 and H7 viruses may mutate
and become highly pathogenic. On April 5th 2006 a dead swan which was found
in Scotland tested positive for the highly pathogenic virus H5N1. On February
3rd 2007, H5N1 was confirmed on a poultry farm in Holton, Suffolk. A 3 km Protection
Zone (PZ) and 10 km Surveillance Zone (SZ) were imposed along with a wider
Restricted Zone. On March 12th 2007 the restrictions around the farm in Holton
were lifted. Only the movement of meat produced from birds originating within
the PZ that were killed prior to the PZ merging with the SZ will need to continue
to be licensed and reported. A Food Standards Agency (FSA) investigation has
thoroughly examined the possibility that food waste at the Bernard Matthews
cutting plant at Holton may have been stored inappropriately. The investigation
concluded that there was no evidence of any offences under the Animal By-Products
Regulations 2005.
All
of the evidence collected indicates that the infection has not spread
beyond one site. Defra have not yet located the exact source of the
infection but the lack of evidence of another outbreak indicates that
the risk of spread of infection has now reduced. European Union (EU)
trade will recommence from the restriction zones and Defra are working
with exporters, British Embassies overseas and non-EU countries’ veterinary
authorities to try to keep export markets open and to facilitate exports (1).
Transport
The catching and transport of birds prior to slaughter can cause considerable
pain and distress. Each catcher will hold several birds upside down by
their legs and cram them into crates which are then loaded onto lorries.
Dislocated hips, broken wings and legs, and bruising are common occurrences.
The process of catching, loading, transport and unloading causes serious
injury and even death to a significant number of broilers, the amount may
be as high as 18 to 35 million across the EU(2). Transport to
slaughter can be a considerable distance and the birds may be exposed to
extremes of weather. Cold, heat, stress, suffocation and shock all take
their toll.
Slaughter
Broiler chickens are slaughtered at just 6-7 weeks of age (a chicken's natural
lifespan is around 7 years). Over 800 million broiler chickens were slaughtered
in the UK in 2006(1). On reaching the slaughterhouse, broiler
chickens are removed from their crates and hung upside down shackled by
their feet to a moving line whilst still fully conscious. Their heads and
neck are dragged through an electrically charged water bath designed to
stun the birds, rendering them unconscious. The moving line then takes
the birds to an automatic neck cutter. Birds are then bled before entering
a scalding tank to make the plucking easier. Broilers often experience
pain and struggle while hung in shackles, and they may suffer during the
slaughter process. It is estimated that over 50 million broilers across
the European Union may be slaughtered while not fully unconscious(2).
It is essential that a sufficient stunning current is used and that both
carotid arteries (the major blood supplies to the brain) are cut to reduce
the risk of birds regaining consciousness during bleed-out and subsequently
entering the scalding tank whilst still alive.
References and Useful Links
1.
Department for Environment Food and Rural Affairs www.defra.gov.uk/
2.
Compassion in World Farming Trust. 2005. The Welfare of Broiler Chickens
in the EU. http://www.ciwf.org.uk/publications/reports/Welfare_of_Broiler_Chickens_in_the_EU_2005.pdf
3.
Weeks, C. A., Danbury,T. D., Davies, H.C., Hunt.P and Kestin. S.C.
2000. The behaviour of broiler chickens and its modification by lameness.
Applied Animal Behaviour Science 67: 111-125.
4.
Soil Association. Animal welfare - some common questions answered
www.soilassociation.org/web/sa/saweb.nsf/
ae318a5b15f8f08c80256de20033d3be/6d48728c364f4fe780256df3005aaf59!OpenDocument
5.
Universities Federation for Animal Welfare (UFAW). 1999. (4th Edition).
Management and Welfare of Farm Animals.
6.
Compassion in World Farming Press Release. 31.07.06. New research shows
that millions of factory farmed chickens suffer from lameness. http://www.ciwf.org.uk/publications/prs/nr1406.pdf
7.
Ritz. C.W., Fairchild. B.D and Lacy. M.P. April 2005. Litter Quality
and Broiler Performance http://pubs.caes.uga.edu/caespubs/pubs/PDF/B1267.pdf
Further
Information
Any questions regarding this information sheet please contact Gilly Prime -
Information and Research Officer gilly@vegsoc.org
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