International Journal of Comparative Psychology

In

two experiments, 24 immature female broiler breeder fowls housed in two 12-cage battery units in identical rooms received a single daily ration which they ate in 10 min, according to a programme of food restriction. From regular 15-min videorecordings, measurements were made of times spent in mutually exclusive activities (sitting, standing, head out, pacing, preening, object pecking, drinker activity). In Experiment 1, feeding time was 09.00 h in one room and 13.00 h in the other, and all birds were videorecorded in every hour of the (14-h) photoperiod on two lternate days. Differences in behaviour before and after feeding were independent of feeding time. In both rooms, head out and pacing increased before feeding, and object pecking and drinker activity (oral stereotypies) commenced immediately afterwards and then declined. Individual variation in the oral stereotypies was significant, and individuals' mean levels of both stereotypies together were consistent on the two days, but their hourly patterns were less so. Experiment 2 tested the notion of homeostatic control of oral stereotypies, by feeding all birds at 09.00 h and measuring their responses to removal of drinkers and empty feeders (main targets of the stereotypies) for either 0, 1.5 or 3 h before 15.00 h. Each cage tier received each treatment once, over three alternate days when all birds were recorded on video between 12.00 and 18.00 h (lights ofQ. During removal of feeders and drinkers, partial suppression of object pecking and total suppression of drinker activity were balanced by corresponding increases in sitting, head out and preening. After the return of feeders and drinkers, preening declined and both stereotypies showed evidence of post-inhibitory rebound, but there was no difference between 1.5 and 3 h removal treatments. The results concur with earlier evidence  indicating that preening can substitute with oral stereotypies, and it is suggested they may demonstrate homeostasis in total (substitutable) oral activity over the whole test. Conceivably, homeostasis of arousal may underlie changes in broiler breeder behaviour before and after feeding time.