Behavior, production, and well-being of the laying hen. 2. Individual variation and relationships of behavior to production and physical condition

Variation of behavior among hens and the relationships of behavior to measures of production and physical condition were investigated. The birds were 384 pullets from the mating of two stocks of males, obtained from a commercial breeder, to females from a third flock. The birds were housed as pairs in laying cages at 22 and 20 wk of age (Hatches 1 and 2, respectively). The laying phase was divided into 28-day periods. In Periods 1, 3, 5, 7, 9, and 11, samples of hens were video recorded for 8 h. In Period 13, direct visual observations were made of the behavior of individually identified hens. Eleven production-related variables were recorded throughout the laying phase. Feather scores were assessed in Periods 3, 6, 9, and 12. Body weight, lesions to the feet, and claw length were recorded in Periods 6 and 13. Spearman rank correlations were calculated between video-recorded behavioral variables and measures of production and physical condition. The data from direct visual observations were used for heritability estimates of behavioral traits. Eating and standing were positively correlated with egg production, whereas sitting and, for hens derived from male parental Stock 1, resting were negatively correlated with production. Inactivity also coincided with poorer plumage condition and higher body weight. For the offspring of male parental Stock 2, behavioral actions frequently performed in stereotyped manner, e.g., cage pecking and toe pecking, were positively associated with egg production. No significant additive genetic variation for behavior was evident among sires; however, for dams, fairly large heritability estimates occurred for a number of behavioral states. The apparent absence of additive genetic variability among sires for behavior may have been due to genetic fixation at gene loci which control behavior in the stocks acquired from the commercial breeder.