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Purpose of guidance

This guide examines current practice, its potential advantages and disadvantages, and provides best practice recommendations for group-stun systems. Following the guidance will help to progress the flow of animals through the stun-pen and improve welfare standards. The guide also suggests ways to further advance the welfare of animals slaughtered in group-stun situations.

What is group-stunning?

Group-stunning is a process where a number of sheep, goats, smaller pigs and young calves (typically 10 – 15) are placed in a stun-pen in order to restrain them prior to slaughter. The size of the stun-pen will vary but should not permit too many animals to be heldin it and will often include a crowding gatewhich allows the size of the stun- pen to be reduced such that, as the numberof animals declines, thereis less room for the remainder to move away from the operator.

Group-stunning pens can be used for both electrical and mechanical stunning methods. The design and operation of these systems has changed littlefor many years.

• Group-stunning of sheep, pigs, calves and goats is common practice, particularly in small to medium sized abattoirs.

• The system is simple and animals are not separated and / or physically restrained prior to stunning.

•Group-stunning allows more than one species to be slaughtered through the same system.

In a typical system, a group of animals will be brought into the stun-pen.

An individual animal will be stunned, shackled, attached to the elevator and conveyed to the

bleed area.

•The slaughterman will continue to stun,shackle and hoist individual animals.

Further reading:

Electrical Stunning of Red Meat Animals– Guidance Notes No. 4 HumanSlaughter Association 2005 Available at : ......Food Standards Agency2017

Advantages of group-stun systems

  • Animals are not isolated and move freely together.

  • Animals are not actively restrained and consequently they may feel calmer.

  • Specialised handling equipment is not required.

  • The system is flexible in terms of species,size and operator.

  • Group-stunning systems are easy and cheap to clean and

  • maintain.

Disadvantages of group-stun systems

Overcrowding in the stun-pen may cause a number of

issues including:

  • Injury due to escape / crushing by other animals.

  • Increased chance of mis-application of stunning


  • Increased chance of delayed stun-to-stick times due to difficulties

in shackling.

  • Fewer animals within the stun-pen means there is more room for them to move around, thus the use of a crowding gate is recommended.

  • Working in a group-stunning pen is very arduous and operator fatigue is a significant problem.

  • Stun accuracy is dependent on the skill of the operators and fatigue will affect the operators ability to stun animals accurately.

What is a good group-stun?

In good group-stun systems animals will:

move easily into the stun-pen locate themselves close to the elevator stand still have their heads in an easily accessible position

be suitably restrained for stunning, either by the design or another person.


Legislation relating to welfare in the slaughterhouse include:

•Council Regulation (EC) No 1099/2009 on the protection of

animals atthe time of killing

•The Welfare of Animals atthe Time of Killing (Wales)

Regulations 2014, SSI 951

•The Welfare of Animals atthe Time of Killing (England)

Regulations 2015, SI 1782

•The Welfare of Animals atthe Time of Killing (Scotland)

Regulations 2012, SSI 321

•The Welfare of Animals at the Time of Killing Regulations(Northern Ireland) 2014, 107

Key legal requirements

Council regulation (EC) No 1099/2009:

Article 2(p) – ‘restraint’ means the application toan animal of any procedure designed to restrict its movements sparing any avoidable pain,fear or agitation in order to facilitate effective stunning and killing.

Annex II, 3.1 – Restraining equipment and facilities shall be designed built and maintained to:

a) optimise the application of the stunning or killing method; b) prevent injuryor contusion to the animals;

c) minimise struggle and vocalisation when animals are restrained;

d) minimise the time of restraint.

The Welfare of Animalsat the Time of Killing (England & Wales):

18. No personmay stun or killan animal without restraining it in an appropriate manner.

22. The business operator and any personengaged in the stunning or killing of an animal must ensurethat an animal which is to be stunned or killed by mechanical or electrical means applied to the head is presented in such a position that the equipment canbeapplied and operated easily, accurately and for the appropriate time.

23. (1) The business operator and any personengaged in the stunning or killing of an animal must ensurethat any instrument, restraining equipment, installation or other equipment which is used for stunning or killing is used in such a way as to facilitate rapid and effective stunning or killing.

(2) In the case of simple stunning, no personmay stun an animal unless it is possible to kill it without delay.


The Welfare of Animalsat the Time of Killing (England & Wales):

31. (1) A person engaged in the bleeding or pithingof an animal which has been simple stunned must ensure that the animal is bled or pithedwithout delay after it has been simple stunned.

(2) A person engaged in the bleeding of an animal which has been simplestunned must ensure that the bleeding is -

(a) rapid, profuse andcomplete; and

(b) completed before the animal regains consciousness.

42. (5) Where one person is responsible for the simple stunning and pithing, or for the simple stunning, shackling, hoisting and bleeding, of animals other than birds or rabbits or for some of those operations, such operations must be carried out by that person consecutively in respect of one animal before being so carried out by that person in respect of another animal.

WATOK (Scotland)2012 Schedule 1


(1) No person may stun or slaughter an animal without

restraining it in an appropriate manner in such away as to spare the animal avoidable pain, distress or suffering.

(2) The business operator of a slaughterhouse and any person engaged in the stunning or slaughter of any animalmust ensure that any animal whichis to be stunned or slaughtered by mechanical meansapplied to the head is presented in such a position thatthe equipment can be applied and operated easily, accurately andfor the appropriate time.

12. (1) Without prejudice to the generality of paragraph 3.2 of Annex III, if an animal is bled after simple stunning, no person may cause or permit any further dressing procedure or any electrical stimulation to be performed on the animal before the bleeding has ended and in any event not before the expiryof

(d) in the case of sheep, goats,pigs and deer, a period of not less than 20 seconds.

Better practice recommendations

When deciding the optimum group size for your system,consider stun-pen area, species and size to be stunned, how many operators are in the stun-pen and the original size of the group.

It is contrary to good practice to visually isolate sheep, therefore the stun-pen should be refilled when no fewer than two animals remain in the stun-pen, provided more animals are available.

Any cables for stunning equipment should be provided with support above the stun-pen to prevent them hanging down and potentially causing animals to become tangled in them.

Move animals forward only when there is space ahead.

Ensure lighting enables operators to see clearly and use it to encourage animals to enter the stun-pen.

Reduce background noise and switch off elevator when not in use.

The stun-pen should be kept clean at all times with any blood spill removed as quickly as possible.

A back up method of stunning must be immediately available at all times.

The stunning tongs should be cleaned at regular intervals to prevent the build-up of wool and debris.

Use calm handling techniques when moving animals.

Ensure walls of the stun-pen have no projections on which animals or operators may injure themselves (design and build to prevent injury is a statutory requirement).

There should be suitable flooring and drainage to prevent slipping.

Animals should be prevented from escaping into the slaughter-hall from the stun-pen.

If swing-doors are used to prevent animals escaping the stun-pen, they should be baffled to reduce excess noise.

If there is a delay in the slaughter process, ensure that animals are returned to the lairage or provided with water.

Animals should not be left unattended in the stun-pen.

Fit elevators with an easily accessible emergency stop button. Stun-to-stick times should not exceed 15 seconds for head only electrical stunning.

Improvements to group-stunning systems

  • A system which incorporates a stun-pen design that can be reduced in size to reflect the number of animals has the potential to improve the group-stunning system through a number of ways. Typically this would be achieved by using a crowding gate.

  • A crowding gate system can be used to passively restrain animals by reducing the floor space available. They are then less likely to move around the stun-pen, as the number of animals within the stun-pen reduces. Consideration should be given to ensuring that the remaining available space permits handling and stunning of animals with no welfare concerns.

  • A barredgate, through which animals can see others, will encourage them into the stun-pen.

A crowding gate can also be used within the pen to restrain fractious animals.

Stun to stick intervals

  • Best practice indicates that animals should be bled within 15 seconds of head-only electrical stunning to ensure they do not begin to recover consciousness before they die of blood loss.

  • Stun-to-stick times should be checked frequently to ensure they remain within 15 seconds for head only electrical stunning.

  • When using electrical stunning equipment the cable should allow easy access to all parts of the stun-pen to enable adequate use of the stunning equipment (the electrodes to be applied in a position that spans the brain).

  • Elevator design is critical; the speed,height and number of pushers all affect the time it takes to get the animals to the bleed area.

  • An adequate number of shackles for the animals in the stun-pen must be available before any stunning takes place.

  • Where a second person sticks the animals he or she should be in place before stunning commences.

  • The bleed area should be as close to the stun-pen as possible.

Before changing or introducing a new group- stunning system,consider:


Will it complywith legislation? Will it enableminimum stun-to-stick times to be met?

2.Flexibility. Will it adapt to the future: Building changes? Operational changes? Species/sizes?

3.Usability / reliability. Will it beeasily:

  • Installed?

  • Operated?

  • Inspected?

  • Maintained?

  • Cleaned?

4.Environmental factors. Have you considered: Lighting?


Noise? (for both operator and animals)

5.Human factors

  • Will it be safe for humans?

  • Will it be easy to operate?

  • Will it make handling easier?

  • Will staff be consulted about it?

6.Animal factors

  • Will it be suitable for different species?

  • Will there be a risk of injury to animals? (there is a statutory requirement for restraining equipment and facilities to prevent injury)

  • Will it prevent unnecessary stress? (statutory requirement) Will animals move into it easily?

7.Future considerations

  • Will it meetthe needs of your business?

  • How canyou improve handling and flowinto and

  • through the stun-pen?


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