Isolation-induced social pecking in domestic chicks: Contemporary correlates and sequelae

Abstract

Aspects of the social pecking of domestic chicks in a free response situation were examined in a series of experiments. It was proposed that a dual pattern of responses involving (a) a preponderance of pecks at the head of a conspecific, and (b) heightened emotionality (as indicated by the emission of distress calls) might be taken to reflect an aggressive tendency, and evidence was reviewed that showed that a brief period of isolation was a sufficient condition to elicit such a pattern. The main questions asked in this paper are: (a) whether the gender of a chick had a material influence on the incidence of such social pecking, and (b) whether orders established in pecking exchanges reflected a unidimensional social ordering among chicks. In the 1st set of studies the effect of the sex of subject on rates of social pecking was tested. While an isolation procedure clearly produced the dual pattern of heightened head pecking and calling, reliable sex differences were not in evidence. In a 2nd study, concerned with the generality of social orders as observed in social pecking exchanges, the isolation procedure again was sufficient to produce apparently aggressive reactions but the resulting peck orders between chicks did not predict success in later tests when the same 2 subjects were pitted against one another in either approach or avoidance competitive tasks. These results are discussed in terms of the relationship of infant aggression to adult aggression, and suggestions are made for a revised view of the development of the aggressive behavior of fowl.

Components of aggression in chickens and conceptualizations of aggression in general.

“…Studies with mice parallel the rat literature (Fredericson, 1952;Rowe & Edwards, 1971), and a set of researches indicates that the components or patterns of aggressive displays in certain fishes are not uniformly influenced by experiential and environmental factors (Clayton & Hinde, 1968;Davis, 1975;Shapiro & Schuckman, 1971). Further, success in peck exchanges between young chicks does not correlate with their success in limited access tests (Rajecki, Nerenz, Barnes, Ivins, & Rein, 1977). Taken together, this growing body of evidence suggests that in the study of any species it may be necessary to forego the assumption that there is some unitary factor in all modes of aggression.…”

Mediating factors in chick social pecking: II. effects of exposure to movement

“…The chicks were hatched communally and were transported in perforated chick cartons. Prior research with hatchlings has revealed that isolation produces com-*Intersubject pecking in hatchlings has been attributed to an aggressive motivation by a number of writers based o n a) the force of the peck [ducklings: Hoffman et al, 19741 ; the reaction of the recipient of the peck [ducklings: Hoffman and Boskoff, 1972;Hoffman et al, 19751 ; and c) peck locus [chicks: Rajecki et al, 1976;Rajecki, Nerenz et al, 1977;Rajecki et al, 19781. Further, recent data from our kdboratory indicates that d) in chicks and poults there are qualitative differences in vocalizations emitted during bouts of voluntary exploration of a novel test area (which included many pecks at the physical environment), compared with aggressive encounters wherein the hatchlings pecked predominantly at the head of their opponent [Rajecki et al, in preparation]. parable patterns and levels of social pecking in chicks with or without brief prior visual and tactile contact with broodmates [cf.…”