Chapter 6: Poultry

Before being slaughtered birds are subjected to a number events that are stressful and can lead to physical injuries, thermal stress, weight loss and in extremes to death. Catching and crating of birds is the major factor for introducing injuries like leg and wing bruising, broken or dislocated wings. Catching method, catching crew and the type and condition of the crates will all contribute to the risk on injuries. Feed withdrawal prior to transport is applied with the objectives of reducing wetness of birds during transport and allow the gastro-intestinal tract to empty prior to processing. However, the process can create a negative energy balance within the birds during the transport phase, leading to prolonged hunger and reduced ability to thermoregulate. Transport conditions, such as loading density, ventilation, vehicle design and protection from external weather conditions contribute to heat or cold stress. Thermal stress, both hot and cold, has been identified as a risk factor for increased mortality levels.

After arrival, poultry in the containers are placed in a lairage area. In lairage birds should be protected from adverse climatic conditions. Before stunning, birds are taken out of the containers either by hand or automatically depending on the type of container and stunning system. Electrical stunning involves shackling of birds in inverted position before stunning. Factors, such as electrical frequency and current, influence the success of the stun and carcass quality. High frequencies with low currents lead to ineffective stunning whereas low frequencies with higher currents lead to haemorrhages.

Gas stunning methods are an alternative to electrical stunning. Different type of birds, like chickens, turkeys, ducks, geese, are effectively stunned by exposure to different gas mixtures. However, induction of unconsciousness is not immediate and will induce respiratory distress before loss of consciousness.