Social discrimination and aggressive pecking in domestic chicks.

Abstract

Free interaction among 192 White Leghorn chicks involved inter-S pecking. During tests as early as 1 day after hatching, socially reared Ss showed reliable social discriminations by pecking more at strangers than at cage mates. Compared with socially reared birds, Ss reared in isolation exhibited certain exaggerated or atypical response patterns. Patterns included heightened rates of inter-S pecking, a pronounced tendency to peck at the head, elevated emotionality as reflected in the distress call, and the failure of pair-mates to show matched rates of environmental pecking. Inferences are drawn from these patterns, with the conclusion that infantile inter-S pecking in chicks may be based on aggressive rather than strictly exploratory tendencies. Findings are discussed in terms of the development of a basic tolerance for conspecifics and early social orderings. (52 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved)