Correlates and consequences of allopecking in White Leghorn chickens

Feather pecking in domestic fowl is considered a serious welfare and economic problem. Although a number of studies have proposed causal explanations for this behaviour, relatively little is known about which forms of pecking result in damage and how they relate to other types of social pecking. This study compared the frequency, consequences and social correlates of feather pecking and other types of allopecking by observing 24 groups of five male and 23 female, White Leghorn chickens between the ages of 10 and 18 weeks. Aggressive pecks were the most frequent type of allopecking observed, followed by allopreens, feather pulls, light pecks and toe pecks. Aggressive pecks usually occurred in the context of feeding while light pecks were most often received while a bird was dustbathing. Birds with damage to their plumage or integument received more light pecks, toe pecks and, to a lesser extent, feather pulls than birds without damage. In general, males delivered and received more allopecks than females. Male dominance rank was not related to any form of allopecking except aggressive pecks. In addition, the frequencies of different types of pecking were not intercorrelated. These results suggest that several forms of allopecking may result in damage. Therefore, future studies on the causes of ‘feather pecking’ should examine damaging forms of allopecking such as light pecks, toe pecks and feather pulling in more detail. Understanding ‘feather pecking’ will require studies of the motivational and environmental circumstances that influence these distinctive forms of allopecking.