PART SEVEN: POULTRY SLAUGHTER
According to the MHS, there are 77 slaughterhouses licensed
to kill chickens by mainstream methods and 50 licensed to
kill turkeys (10). In 1998, 846 million birds were in the
UK (a percentage of these were killed by religious methods)
- so the daily kill at each plant is vast.
65 out of 77 plants stunning chickens and 34 out of 50 plants
stunning turkeys use the electric waterbath. This amounts
to 73.9% of plants.
1.1% of plants plant use gas stunning and very low throughput
premises tend to use an electric hand-held stunner. 12.5%
of plants do not pre-stun at all (see Viva!'s "Going
for the Kill" report on religious slaughter).
Dislocation of the neck
UK slaughter legislation states that birds may be killed
by decapitation or dislocation of the neck. These procedures
do not require a licence provided that they are carried out
on premises forming part of an agricultural holding on which
the bird was reared. (5)
Decapitation is not widely practised but neck dislocation
is the most widely used method of slaughter on small-scale
Gregory and Wotton expressed concern about the effectiveness
of neck dislocation in poultry. They tried crushing and stretching
the necks of poultry (method 2 works in a similar manner to
manual neck dislocation) and concluded that, "neither method
consistently produced concussion and it is uncertain whether
they cause instantaneous unconsciousness." (58)
Researcher Roger McCamley says that, "There is certainly
a potential for welfare problems to arise when small scale
seasonal producers kill large birds by neck dislocation. Usually,
no training will have been sought or received and because
of the small number and infrequency of slaughtering, little
expertise in slaughter will be obtained." (57)
Untrained staff should not be permitted to kill birds on
farms by methods which are not guaranteed to cause immediate
unconsciousness. Scientists are not able to guarantee that
neck dislocation causes instantaneous unconsciousness and
birds will suffer far more at the hands of untrained workers.
'Dead on Arrival'
The Meat Hygiene Service report that "Despite the high level
of care and attention to the transportation of birds as recorded
on the checklist, the average percentage of birds that died
in transit was recorded nationally as 0.2% of the weekly throughput."
(10) This translates into 1.7 million birds each year.
Why do birds die?
Gregory and Austin examined the reasons for birds being "dead
on arrival" in a paper published in The Veterinary Record.
Death rates at the plant investigated were 0.19% on the day
they investigated - slightly lower than the current national
The researchers concluded over half the birds had died from
heart failure and say, "Presumably the physiological responses
associated with the stress of catching, loading and transporting
the birds had been too much for the cardiovascular system
to cope with".
The second most common cause of mortality was found to be
dislocation of the femur (thigh bone) at the hip joint. This
was associated with profuse haemorrhage. It occurred mainly
in larger birds and the researchers say that, "It is thought
that catching and carrying large birds by one leg is conducive
to dislocation of the hip, and that catching by two legs would
help reduce this problem." However, they point out that catching
by two legs would slow down the catching rate, meaning that
more staff (and therefore more money for wages) would be needed.
They caution that the survey will not have revealed the full
extent of birds arriving with hip dislocations because they
only counted birds who actually died. Any who survived would
have, "entered the processing plant in the normal way".
Other birds died from a crushed skull, a cause of death which
occurred most frequently in transporters which used plastic
drawers. The researchers deduce that, "insufficient care was
taken to ensure that birds were crouching down when the drawers
were being closed."
So, before birds even arrive at the slaughter plant, they
will have to endure the stress of catching, transportation
and loading - procedures so stressful that they can cause
birds to have heart attacks. Careless handling means that
birds' skulls can be crushed and that dislocated hips are
commonplace. Viva! is concerned to note that Dead on Arrival
rates for birds show no sign of falling.
The process of hanging live birds upside down prior to slaughter
causes extreme stress and has led scientists to investigate
alternative options for the stunning and slaughter of poultry.
Despite this, the vast majority of birds in British abattoirs
continue to be shackled alive.
Chickens kept on modern factory farms have been bred to grow
far faster than they would naturally and this places a huge
strain on their undeveloped limbs, causing painful crippling.
Broiler chickens' bones are unable to form properly and what
should be hard, calcified bone is frequently nothing more
than soft cartilage. As a consequence, their skeletons fail
to grow properly and their legs bend or break under their
rapidly ballooning weight (60). The Agriculture and Food Research
Council have stated that up to four fifths of broiler chickens
have broken bones and deformed feet and legs or other bone
Shackling is incredibly painful for turkeys because of their
immense weight. They are bred to have as much meat on their
breasts as possible. But no exceptions are made even for the
hugely overweight male breeding birds who can top 27 kg (about
60 lbs) - as much as an eight or nine year old child. The
strain on their hip joints - which are often diseased - is
enormous and painful.
Professor John Webster says that, "...certain welfare abuses
are intrinsic to the [slaughter] system. Suspending birds
upside down on shackles must induce some degree of fear. More
seriously, this procedure must seriously exacerbate the intensity
of pain in chickens and especially the heavier turkeys with
chronic leg disorders. The stunning process cannot guarantee
100% efficiency. Finally, the whole stressful procedure takes
UK legislation says that turkeys can be shackled for up to
six minutes and other birds for up to three minutes before
slaughter (5). The idea behind slaughter welfare legislation
is - supposedly - to ensure the humane treatment of animals.
Viva! believes that the law legitimises horrific suffering
for birds in the run up to slaughter. It is particularly barbaric
to allow turkeys with chronic leg disorders to be hung upside
down by their legs for a full six minutes.
The law also states that "appropriate measures" should be
taken to ensure that shackled birds are "in a sufficiently
relaxed state for stunning or killing to be carried out effectively
and without undue delay." A bird must not be shackled, "in
such a manner as to cause it avoidable pain or suffering."
(5) The whole procedure clearly causes pain and suffering
- but exactly which elements are avoidable is not made clear.
No licence is required for shackling poultry prior to slaughter.
The procedure may therefore be undertaken by untrained individuals
whose competence has not been officially assessed (16). Line
speeds can carry up to 9,000 birds an hour (62) meaning that
operators will have to shackle birds at high speed.
Any slaughter system which depends on poultry being shackled
intrinsically causes suffering. Viva! is appalled that the
vast majority of UK poultry abattoirs continue to depend on
this outdated, cruel system.
Painful electric shocks
When entering the electric waterbath, a bird's wings may
be hanging lower than the head, meaning that the bird will
suffer a painful electric shock. This is a particular problem
for turkeys. The Scientific Veterinary Committee of the EU
say that, "The prevalence of pre-stun electric shock in turkeys
is high (about 80%)." (17)
Poultry scientist A.B.M. Raj says that various methods have
been tried in an attempt to reduce this welfare problem but
that, "In spite of these developments, a considerable proportion
(6%) of turkeys still receive prestun electric shocks." (63)
35 million turkeys are killed annually so the 6% figure means
that 2.1 million turkeys are still receiving painful electric
shocks each year.
Birds inhale water
Gregory & Whittington identify another problem. After
conducting an experiment, they conclude that, "chickens can
and do inhale water during electrical stunning in a waterbath.
No remedy for this is available at the moment." (64) The scientists
explain that, "some birds defecate during stunning and hence
foul the water of waterbath stunners." So, at stunning, live
birds inhale faeces when they are dipped into the electric
waterbath. This is perceived as a particular problem from
the meat hygiene perspective because the fluids can leak out
of the lungs and cause contamination.
The Electric Waterbath
Inadequate stunning is a real problem within the poultry
industry. Ducks and geese in particular are known to "swan
neck" - raising their heads when entering the waterbath and
so avoiding full immersion. The Scientific Veterinary Committee
of the EU say that it is especially difficult to stun ducks
and geese effectively. They say that, "Heads of ducks and
geese are not always immersed in the waterbath due to their
anatomical disposition." (17)
The Meat Hygiene Service admit that, "Due to the ability
of the birds to move during entry to the stunner, there will
always be a small proportion of birds which are not stunned
due to failing to make contact with the water...". (10) These
birds are supposed to be removed from the line and killed
by a "back up" killer - usually by decapitation.
The birds are fully conscious while they are having their
Birds will pass the back-up killer at a speed of up to 150
birds a minute (62), so he will only have about half a second
to check each one. If birds get missed, they will continue
on to the neck-cutter whilst still conscious.
Birds regain consciousness
The aim of modern waterbath systems is supposedly to induce
a cardiac arrest in birds so that they die and have no chance
of regaining consciousness. However, not all birds have a
cardiac arrest and the RSPCA say that, "Many birds are improperly
stunned and recover consciousness before slaughter." (65)
Broiler chickens have been shown to have their somatosensory
evoked responses abolished (an indication of unconsciousness)
for at least 52 seconds after stunning in an electric waterbath.
Another study showed that "end of lay" hens recover consciousness
after as little as 22 seconds (66). Almost 90% of turkeys
who do not develop a ventricular fibrillation show some recovery
of their somatosensory evoked responses within 60 seconds
of stunning (67).
A research paper by N.G. Gregory states that the time between
stunning and neck cutting in broiler chicken plants varies
between 14 and 37 seconds (68).
Gregory says that birds retain their brain function during
exsanguination for longer than mammals. He shows a graph which
reveals that it around 1.5 minutes for chickens and ducks
to lose brain responsiveness after a cardiac arrest; almost
3 minutes after both carotid arteries are severed and around
5 minutes after one jugular artery and one carotid artery
These results are disturbing even if you take the optimistic
view that the electric waterbath stuns birds for 60 seconds.
Chickens will regain consciousness before they lose brain
responsiveness if they do not have a cardiac arrest when they
enter the waterbath.
"End of lay" hens only lose consciousness for 22 seconds
and so Viva! is convinced that hens regain consciousness before
they lose brain responsiveness if they do not suffer a cardiac
arrest. We fear that the same thing is also happening with
turkeys, ducks and geese.
How many regain consciousness?
N.G. Gregory says that, "some authorities take the view that,
from the welfare standpoint, it is best to induce a cardiac
arrest at stunning in at least 90% of birds." (30) However,
some plants are now using a system of high frequency stunning
which only aims to stun birds rather than kill them by cardiac
If we take the optimistic view that 90% of birds have a cardiac
arrest at stunning and are unconscious until they die, 62
million electrically stunned birds will not have a cardiac
arrest. They will be stunned for 60 seconds but they will
not die for almost 3 minutes and so they will regain consciousness.
62 million chickens, turkeys, ducks and geese are regaining
consciousness in British abattoirs each year.
How many birds are conscious when they enter the scalding
Let's assume that birds will only be conscious on entering
the scalding tank if they have one carotid artery cut at slaughter.
In this case they will take around 5 minutes to die yet legally
they only have to be left to bleed out for 2 minutes. They
will regain consciousness after only one minute.
14 abattoirs appear to use automatic neck-cutters which only
sever one carotid artery. 73.9% of these - or 10 abattoirs
- will use the electric waterbath. If these abattoirs slaughter
10% of birds they will kill 84 million birds a year. 90% will
have a cardiac arrest at stunning, leaving 8.4 million who
will only have one carotid artery cut and will therefore be
conscious on entering the scalding tank.
8.4 million chickens, turkeys, ducks and geese are conscious
when they enter the scalding tank.
Constant current waterbath stunners
One of the problems with electrical stunning is that the
amount of current which passes through each individual bird
varies according to the impedance of the bird to the current.
Mohan Raj says that a waterbath stunner that can deliver a
present constant current to each bird in the waterbath has
been developed recently and believes that this improvement
could enhance bird welfare (63). Two years later, Viva! wrote
to the Meat Hygiene Service to ask whether UK abattoirs are
using these new stunning systems. Principal MHS OVS Jane Downes
replied that she did not hold any information on this subject.