Knacker's yards and farms: restraining, stunning and killing animals
Know which licence or certificate you must have to restrain, stun or kill animals which are not for human consumption, and how to carry out these operations.
Applies to England
This guidance is for knacker’s yards and farms processing animals not for human consumption.
You must have a welfare of animals at the time of killing (WATOK) licence or a certificate of competence (CoC) if you:
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restrain animals for stunning or killing
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stun animals
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check stunning has worked
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shackle or hoisting live animals
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bleed live animals
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pith animals you’ve stunned
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carry out an assessment of effective pithing
This applies to:
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horses and donkeys
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cattle, sheep, goats and deer
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pigs
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rabbits
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poultry
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ostriches
You must hold a WATOK licence for each procedure you carry out. You risk losing your licence or [CoC] (https://www.gov.uk/guidance/get-a-certificate-of-competence-or-licence-to-slaughter-or-kill-animals) and you may be committing an offence if you do not follow these and other WATOK requirements.
Restraining animals
You must restrain an animal in the appropriate way before you stun or kill it.
Your equipment for restraining animals must:
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be in good working order
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be maintained and checked by following manufacturers’ instructions
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be used by following manufacturers’ instructions
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allow you to stun or kill an animal effectively and quickly
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present the animal’s head in a way that allows you to stun it accurately
You must only put animals into restraining equipment, including head restraints, when you’re ready to stun or kill the animal.
Stunning pens for cattle
You must use a stunning pen or restraining pen for adult cattle, including bovine animals like buffalo and bison.
You must only use restraining equipment in the way described in the manufacturer’s instructions.
Stunning pens and restraining boxes must:
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be in good working order
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be maintained and checked (follow the manufacturer’s instructions)
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be able to fit one animal at a time without discomfort
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stop the animal from making any large movements forwards, backwards or sideways
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allow complete access to an animal’s forehead, for accurate stunning
Restricting cattle head movements
Stunning pens and restraining boxes for cattle must have a device to stop an animal’s head moving up and down so you can stun it accurately.
The device must release an animal’s head immediately after stunning and should not cause the animal pain, distress, or suffering.
Shackle lines
Shackle lines must be designed for the size, type and weight of the poultry you’re handling at your knacker’s yard.
The shackles must be the right size and shape for the legs of the birds so that electrical contact can be made without hurting them.
The shackles must be wet. You must shackle both legs.
Position of shackle lines
You must position shackle lines so that you can:
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reach the whole shackle line easily and you can take an animal off it at any time if it suffers pain or distress
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easily reach the equipment controls at any time
If you’re hanging up poultry before stunning or killing, the birds must:
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be relaxed
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not touch any objects or each other, even when their wings are stretched out
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not be disturbed
Speed of shackle line
The shackle line must move slowly enough to make sure you:
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do not distress the birds
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can take any measures to prevent pain, suffering or distress
Maximum hanging time
You must only hang conscious birds on a shackle line for:
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3 minutes (turkeys)
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2 minutes (other poultry)
Restraining methods you must not use
If you’re restraining animals, you must not:
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suspend or hoist them while they’re conscious, except for poultry
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use electrical stunning equipment or shock devices to immobilise an animal
Animal stunning and killing
You must stun all animals before you kill them and then kill them immediately.
You need to make sure the animal stays unconscious so it cannot feel pain when you kill it.
Simple stunning
‘Simple stunning’ causes an animal to lose consciousness, but does not kill it instantly.
Equipment for stunning or killing
Any equipment you use for stunning or killing must:
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stun or kill rapidly and effectively
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be in good working order
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have the manufacturer’s instructions on how to operate it
You must have back-up stunning equipment available immediately on the spot in case your main equipment fails.
Maintaining your equipment
You must maintain equipment following the manufacturer’s instructions.
You must keep maintenance records for at least a year. An inspector can ask to see them.
Checking that your stunning method is effective
When you’ve stunned an animal, you must check if it’s unconscious before you kill it. If an animal is still conscious you must immediately re-stun it.
You must have a WATOK licence or a CoC for checking the effectiveness of stunning. Your knacker’s yard standard operating procedure should also list what monitoring procedures will be used.
If you find an animal that has not been properly stunned, you must immediately re-stun it and follow your knacker’s yard’s standard operating procedure.
If you’re failing to stun animals properly, you must find out what’s wrong and correct your operation immediately.
Stunning by firearm with free projectile
You can use a firearm to stun all animals – this stunning method kills by causing severe damage to the animal’s brain when the gun is fired. You should fire it at the head and use a cartridge or bullet that will kill the animal instantly. The manufacturer’s instructions will show you what cartridge or bullet to use.
Killing by a percussive blow to the head
You can kill rabbits that weigh less than 5kg by hitting them on the head with a firm and accurate blow, where there are no other permitted stunning methods available.
Electrical stunning
Electrical stunning is a method of simple stunning, and must be followed as quickly as possible by a killing method, such as bleeding.
When you carry out electrical stunning:
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there must be a good electrical contact with the animal
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electrodes must span the brain of the animal and be adapted for the size of animal, for head-only stunning
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the current must be strong enough and you must subject the animal to it for long enough to make them unconscious until death
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you must kill the animal before it recovers consciousness
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you must use the minimum currents set out in table 1
Monitoring electrical stunning
For each animal you stun, your equipment must be fitted with a device that shows the:
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voltage
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current – in amps (A)
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length of time of the stun
The device must be clearly visible to staff carrying out stunning.
If the electrodes do not deliver the right current or voltage for the right amount of time, the device must give a clearly visible and audible warning.
Table 1: Minimum currents for head-only electrical stunning
| Species | Minimum current |
|---|---|
| Cattle 6 months or older | 1.28A |
| Cattle younger than 6 months | 1.25A |
| Sheep and goats | 1.0A |
| Pigs | 1.3A |
| Chickens | 240 milliamps (mA) |
| Turkeys | 400mA |
Head-to-body electrical stunning
If you’re using electrodes on an animal’s head and body, you must use these currents:
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sheep and goats – 1A
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pigs – 1.3A
Waterbath stunning
Waterbath stunning is a simple stunning method for poultry, unless the frequency is equal to or less than 50 Hz. Following the stun, you must kill the animal before it regains consciousness.
To carry out waterbath stunning you must:
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install a waterbath that’s a good size and depth for the birds processed at your knacker’s yard
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be able to adjust the water level for different birds to ensure that there’s good contact with each bird’s head
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make sure the electrode is immersed in water and extends the length of the waterbath
Entrance to waterbath
You must make sure the waterbath does not overflow at the entrance. If it does, you must make sure that poultry do not receive a shock before they’re stunned.
Electrical current and duration
To make birds unconscious immediately and to keep them unconscious until they’re dead, you must make sure:
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there are good electrical contacts
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the voltage is maintained at a strong enough current to ensure every bird is stunned immediately
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you expose the birds for at least 4 seconds
If you’re stunning several birds, you must make sure the current and duration stuns all the birds enough to keep them unconscious until they have been killed by a follow-up method.
Table 2: Electrical waterbath stunning: average current and frequency
| Frequency (Hertz - Hz) | Chickens (average current) | Turkeys (average current) | Ducks and geese (average current) | Quail (average current) |
|---|---|---|---|---|
| < 200Hz | 100mA | 250mA | 130mA | 45mA |
| From 200 to 400Hz | 150mA | 400mA | not permitted | not permitted |
| From 400 to 1,500Hz | 200mA | 400mA | not permitted | not permitted |
Breakdowns
If there’s a breakdown or delay in the shackle line you must be able to:
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access the shackle line or waterbath
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kill any animals that have been stunned but remain in the waterbath
Captive bolt stunning
A captive bolt device can be used for stunning animals. You must use devices in line with the manufacturer’s instructions, including positioning and using the correct strength cartridge or compressed air.
Penetrative captive bolt
You can use penetrative captive bolt devices for simple stunning for all species.
You must check the bolt has retracted to its full extent after each shot. If the bolt has not fully retracted, you must not use the device until it’s repaired.
You must shoot animals in the middle of the forehead. But if you’re stunning sheep and goats that have horns, you can shoot the animal in the back of the head. You must aim the shot just behind the base of the horns and aim towards the mouth.
You must bleed or kill sheep and goats with horns that are shot in the back of the head within 15 seconds of shooting them.
You must not shoot a bovine in the back of the head.
Non-penetrative captive bolt
A non-penetrative captive bolt device can be used as a simple stun, or a killing method for certain species within specified parameters.
Non-penetrative captive bolt: as a killing method
The device can only be used as a killing method for:
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piglets that weigh less than 10kg
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kids that weigh less than 4kg
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lambs that weigh less than 6kg
To be used as a killing method the device must deliver a minimum kinetic energy of:
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27.7 joules (J) for piglets
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27.8J for kids
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107J for lambs
Non-penetrative captive bolt: as a simple stunning method
The non-penetrative captive bolt device is a simple stunning method for:
- cattle under 10kg, sheep between 6kg and 10kg, and goats between 4kg and 10kg
- poultry
- rabbits
- hares
Non-penetrative captive bolt: conditions of use
It can be used for slaughter, depopulation, and other situations for:
- poultry
- lambs of less than 10kg
- kids of less than 10kg
- piglets of less than 10kg
- rabbits
- hares
It can be used for slaughter only for other ruminants under 10kg.
You must apply the device in the proper position and use the correct strength of cartridge or other propellant by following the manufacturer’s instructions to produce an effective stun or kill, as appropriate.
You can find detailed guidance on the use of captive bolt devices at the Humane Slaughter Association website.
Cervical (neck) dislocation of poultry
You can only use manual cervical dislocation if:
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the bird weighs less than 3kg
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there are no other methods available
You can only use manual cervical dislocation on up to 70 birds a day.
You can only use mechanical cervical dislocation if:
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the bird weighs less than 5kg
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there are no other methods available
Gas stunning
Gas stunning is a method of killing pigs in knacker’s yards and poultry on-farm and in knacker’s yards. You must use the gas stunner in line with the manufacturer’s instructions.
You can only use whole house gas stunning for poultry and under the supervision of a veterinary surgeon.
If you’re culling poultry on-farm using gas stunning, you must write to the Animal and Plant Health Agency 5 days in advance.
You must expose each animal to the gas for long enough to kill it.
You must use a gas stunner which allows you to:
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monitor the animals to check they are not suffering avoidable pain, suffering or distress while you’re stunning them
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flush the stunner with air with the minimum of delay if you need to enter the chamber to access the animals in case of an emergency, for example if the machinery breaks down
For pigs, you must make sure the gas stunner and its conveyors:
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do not injure or bruise the animals or compress their chest
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minimise struggling or vocalisation
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allow animals to remain standing until they lose consciousness
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have adequate lighting to allow pigs to see other pigs or their surroundings while on the conveyor leading to the gas stunner, and while in the stunner
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get animals to the point of maximum gas concentration within 30 seconds, if you’re using a high concentration of carbon dioxide
For poultry, you must make sure the:
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gas stunners and their conveyors do not injure the birds
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poultry are put in the stunner in a way that minimises pain, distress and suffering
Gas monitoring devices
Gas stunners must have a monitoring device that displays the gas concentration. The device must be clearly visible to staff.
The monitoring device must display a clear visible warning and sound an alarm if the gas concentration falls below the correct level.
No pig or bird must go into the stunner or remain in it if:
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there’s a problem with the gas stunner
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the alarm goes off
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the gas concentration falls below the correct level
Gas mixtures
To kill poultry by gas, you must use one of the following gas mixtures:
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carbon dioxide at high concentration (except ducks and geese)
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carbon dioxide in 2 phases
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carbon dioxide mixed with inert gases
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inert gases
For pigs you can use:
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carbon dioxide at high concentration
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carbon dioxide mixed with inert gases
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inert gases
You must not use a pure source of carbon monoxide for pigs or poultry.
You must not allow gases to enter the chamber (or the location where animals are to be stunned and killed) in a way that could create burns or excitement. This could be caused by the gases, by freezing or lack of humidity.
You must only stun pigs or poultry by gas if each animal is exposed to the gas for long enough to make sure it’s killed.
Carbon dioxide at high concentration – pigs
The minimum concentration is 80% carbon dioxide. Exposure of conscious pigs to the gas must lead to anoxia (loss of oxygen to the brain).
You must make sure that no pig enters the gas stunner if the carbon dioxide concentration by volume falls below 80%.
Carbon dioxide at high concentration – poultry
The minimum concentration is 40% carbon dioxide. Exposure of conscious birds to the gas must lead to anoxia.
You must make sure that no bird enters the gas stunner if the carbon dioxide concentration by volume falls below 40%.
You must not use a high concentration of carbon dioxide on ducks and geese.
Carbon dioxide in 2 phases – poultry
Expose the animal to gas with a maximum concentration of 40% carbon dioxide. When the animal is unconscious, use a higher concentration of carbon dioxide.
Carbon dioxide mixed with inert gases – pigs
Expose conscious pigs directly or progressively to a gas mixture containing up to 40% of carbon dioxide mixed with inert gases. This will lead to anoxia.
The maximum concentration is 40% carbon dioxide. Direct or progressive exposure of conscious pigs to the gas must lead to anoxia.
Carbon dioxide mixed with inert gases – poultry
For poultry you must make sure that gas concentrations by volume are at most:
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20% carbon dioxide
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5% oxygen
Inert gases – poultry and pigs
Expose conscious animals directly or progressively to gas containing an inert gas mixture (such as argon or nitrogen) leading to anoxia.
You must make sure that the oxygen concentration by volume is 2% or less, for poultry.
Lethal injections
A vet can lethally inject animals with veterinary medicines to kill them.
Kill animals by bleeding or pithing
After you’ve used a simple stunning method on animals, you need to kill them while they’re still unconscious by bleeding or pithing.
Bleeding
To kill an animal by bleeding, you must cut the 2 carotid arteries in its neck.
You must bleed the animal:
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immediately after simple stunning
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as quickly and completely as possible
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before it regains consciousness
If you bleed an animal after simple stunning, you must not dress the animal or stimulate it electrically until:
- bleeding has stopped
- you’ve confirmed there are no signs of life
You must wait for these minimum times until you dress animals:
- 30 seconds – cattle
- 20 seconds – sheep, goats and pigs
- 2 minutes – turkey or geese
- 90 seconds – all other birds
Killing horses
You must kill a horse in a separate room or a bay which is kept specifically for that purpose.
You must not kill a horse:
- in sight of another horse
- in a room where there are remains of another horse or other animal
Hatchery waste
You can only kill chicks that are less than 72 hours old and the killing must be as rapid as possible. You can only use one of the following methods:
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maceration (immediate crushing of an entire animal)
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gas (chicks must die quickly and stay in the gas until they are dead)
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cervical (neck) dislocation but only if there are no other methods available
If using gas, you must use one of the following gases:
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carbon dioxide at high concentrations
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carbon dioxide in 2 phases
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carbon dioxide mixed with inert gases
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inert gases
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pure source carbon monoxide
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carbon monoxide mixed with inert gases
Updates to this page
Last updated 5 June 2023 + show all updates
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Content has been reviewed as part of improvements to the welfare of animals at the time of killing pages. Updates approved by Welfare at Slaughter team.
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Amended non-penetrative captive bolt device guidance because of a change in the law
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First published.