4.4 At the slaughter plant

Post transport handling and environment
Shackling and stunning
Further reading
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Post transport handling and environment

Thermal conditions at the end of the journey must be considered as it can take 2-3 hours to manually unload pullets. Spent hens may also have to wait at the processing plant either on the vehicle or unloaded in modules or stacks of crates. In both instances a well-designed lairage is preferable to remaining outside exposed to the elements. It is important that the birds themselves receive adequate ventilation. The model birds used by Webster et al (1992) and Weeks et al. (1997) indicated that the hens frequently experienced conditions of substantial heat and cold stress in lairage during loading and unloading. Van Niekerk et al. (2014) measured temperatures during transport and lairage. Despite the use of a covered lairage and ventilation, temperatures clearly went up substantially during lairage. Thus the duration of such times needs to be kept to a minimum of preferably less than 1 hour.

Temperature during transport (average ambient temperature 4.5 degrees C)
Figure: Temperature during transport (average ambient temperature 4.5 degrees C). Temperature coding: first letter refers to position on truck (L=left side of truck, M=middle side of truck, R=right side of truck), second letter refers to logger position in crate (L=left, R=right); trucks were 3 stacks of crates wide and 12 stacks of crates long, all crates with loggers were positioned 2-3 stacks from the rear end of the truck.
Temperature during transport (average ambient temperature -4.7 degrees C)
Figure: Temperature during transport (average ambient temperature -4.7 degrees C). Temperature coding: first letter refers to position on truck (L=left side of truck, M=middle side of truck, R=right side of truck), second letter refers to logger position in crate (L=left, R=right); trucks were 3 stacks of crates wide and 12 stacks of crates long, all crates with loggers were positioned 2-3 stacks from the rear end of the truck.

A controlled environment providing adequate ventilation while avoiding excessive wind and air movement (except in hot weather) onto the birds is highly desirable. There should also be sufficient space around each module or stack for effective air exchange and flow. Monitoring the condition of birds and their environment in lairage is as necessary as it is during the journey. In practical terms, birds observed to be panting will become progressively dehydrated and increasingly heat stressed.

Following arrival at the processing plant most end-of-lay hens are manually removed from the containers. Where electrical stunning is used, live birds are suspended by their legs from shackles for conveyance to the bath. Many birds react to this potentially painful procedure by struggling, flapping their wings and attempting to righten themselves. This can lead to injury and reduces the chance that the bird will be effectively stunned prior to slaughter. To reduce the stress of hanging birds in shackles, Liner et al. (2011) found that struggling was reduced through the use of a breast support conveyor. Observations in U.S. slaughter plants showed that providing a breast rub made from strips of smooth conveyor belting will also reduce struggling and flapping.

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Shackling and stunning

Bird welfare is greatly improved when the labour intensive, stressful and often painful procedure of removing them from the containers and hanging them on shackles is eliminated. Controlled atmosphere (gas) stunning of chickens is now the commercial norm in some countries, with welfare and meat quality benefits such as reduced breast muscle haemorrhaging and bone breakages (Raj et al., 1997, Hoen and Lankhaar, 1999). Automation of shackling is has been investigated (e.g. Lee, 2001; Tinker et al., 2005) and is easier with gas-stunned birds than conscious ones that may flap, struggle and experience pain when shackled (Sparrey and Kettlewell, 1994).

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Further reading (by language)

English

Post transport handling and environment

  • Lines, J.A., Jones, T.A., Berry, P.S., Spence, J., and Schofield, C.R. (2011) Evaluation of breast support conveyor to improve poultry welfare on the shackle line, Veterinary Record, 168:129.

Shackling and stunning

Nederlands

Hanteren en omgeving na het transport

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