Genetic Variation in Social Aggressiveness and Competition Effects Between Sire Families in Small Flocks of Chickens , ,

Abstract

EVIDENCE has been accumulated by Guhl, Craig and Mueller (1960) and by Komai, Craig and Wearden (1959) indicating that social aggressiveness within strains of chickens is heritable. Significant associations between social rank and production traits have been reported by Guhl (1953) and Tindell and Craig (1959) within strains, while social “competition effects” between strains were also reported by the latter authors. The current investigation was set up to yield information on the hypothesis advanced by Tindell and Craig (1959) that competition effects might also be present between families within strains. In addition, variation in social aggressiveness was analyzed to furnish further evidence as to the heritable nature of this characteristic. Pullets were obtained from eight sire families of the Cornell randombred control population of White Leghorns (see King, Carson and Doolittle, 1959) to conduct the study. All chicks were hatched, wingbanded and dubbed February 12, 1958. They were raised in …