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Panic in free-range laying hens

PANIC has been defined as ‘frantic and sudden fright’ (MacDonald 1972) and in animals is generally characterised by some form of disorientated, excessive escape behaviour, which is often inappropriate to the situation in which it occurs (Mills and Faure 1990). The term has been used to describe apparently causeless flight in flocks of wild birds (Campbell and Lack 1985). In farmed poultry, panic is an occasional but significant problem which has been reported in both caged and floor-raised hens (Hansen 1976). This can often need only one individual to initially respond fearfully and then be transmitted to other birds very rapidly (Mills and Faure 1990). A range of potentially fearful triggers for poultry have been described: noise (Hansen 1976), human interventions (Golden 1959), potential predators and other unfamiliar stimuli (Payne 1959, Hughes 1961, Ferguson 1968).

The consequences of severe panic outbreaks (such as suffocation and trapping/hanging of birds) can be fatal (Mills and Faure 1990). Episodes of severe panic can also lead to a reduction in egg production (Hansen 1976) and egg shell quality (Hughes and others 1986, Reynard and Savory 1999). Other non-lethal consequences such as bruising, increased food intake, reduced growth rate and feather loss have also been related to panic (Mills and Faure 1990). Thus, the occurrence of panic can have both welfare and economic consequences for the poultry industry.

A wide range of potential variables have been implicated …