Stun Boxes

Stun boxes are principally used for restraining cattle in abattoirs. In some countries these are required by law and must limit the movement of the animal, forwards, backwards and sideways. Stun boxes usually have a guillotine door at one end, through which the animal enters, and a side door through which the animal is removed after being stunned. These side doors may be guillotine-type, partly-revolving or fully-revolving.

The law may also require that a head restraint device is fitted within the stun box to help improve the accuracy of stunning. There are two basic types of installation available: ‘passive’ and ‘active’. Whichever system is installed, it should only be operated by appropriately trained and licensed members of staff.

‘Passive’ head restraints, such as the ‘fixed shelf’, are fitted at the front of the stunning box. These prevent the animal from lowering its head, but do not hold the head fast or involve any moving parts. The performance of this type of device is improved if used in conjunction with a tail-push which prevents the animal moving backwards. ‘Passive’ head restraints are recommended as they improve stunning accuracy without increasing stress on the animal.

‘Active’ head restraints are of two types. The first is the ‘neck yoke’ system consisting of one or two vertical bars which grip the animal’s neck within the stunning box. The bars then retract against the sides of the box when not in use. The second is a ‘head yoke and chin lift’ device, which holds the head right outside the stunning box. Both of these devices improve stunning accuracy but are likely to increase stress on the animal.

Figure: Side views of various passive head restraint shelf designs

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