Aggression and sexual activity in the brown leghorn cock

Twenty-two cockerels were scored singlyfor sexual activity in 2 pens of hens, and then scored for aggressiveness. Two measurements of aggression were obtained by observing each cockerel in 6 individual encounters with six special cockerels that had been trained to fight. These measurements were (i) the number of fights started with one fight per encounter, and fights started with one fight per encounter, and (ii) the time taken to start fighting in each encounter.

After the data had been examined for any possible conditioning effects on the 22 cockerels, the scores for aggression were found to be highly correlated with one another but not with the sexual activity of the male

The number of fights won, drawn or lost were also recorded and the fighting score of each male was found to be significantly correlated with the measurements of aggression, but not with sexual activity.

The cockerels were then divided into three groups, penned, and the peck order position of each cockerel determined. No correlation was found to exist between the peck order position of a cockerel and his score for sexual activity. The practical implications of this are discussed.

The development of the aggressive andsexual drives in young male chicks is briefly described and the relationship between the two drives was examined in young male chicks treated with testosterone propionate. It is suggested that the relative aggressiveness and sexual activity are also uncorrelated in immature cockerels.