Genetic Assessment of the Behavior of White Leghorn Type Pullets in an Open Field

Open field tests were carried out using 17-wk-old pullets derived from two commercial White Leghorn type stocks of males bred to White Leghorn type females from a stock kept at the University of Guelph. Behavioural differences both between and within stocks were investigated, and the heritabilities of the behavioral variables were calculated. The offspring of male parental Stock 1 took longer to manifest pecking behavior than those of male parental Stock 2, and also made less use of the areas of the open field farthest from the starting point. Male parental Stock 1 showed significant variability due to sires for sitting and standing behavior, whereas for male parental Stock 2, variability existed for neck extension and the number of behavioral states manifested. Significant variability due to dams was apparent for several behavioral variables. Heritability estimates ranged from zero to quite high, with those corresponding to the significant sire effects being the highest. The results suggest that the offspring of male parental Stock 2 were the more responsive to social stimuli and were possibly more investigative. Significant sire and dam effects indicate that there are differences in the way individual chickens respond to novel environments, and that these responses may be modifiable through selection.