INGESTIVE BEHAVIOR AND GROWTH WHEN CHICKS FROM LINES DIFFERING IN FEED CONSUMPTION ARE REARED SEPARATELY OR INTERMINGLED

Ingestive behavior, livability, and body weight were measured in lines of chickens selected for high (HW) and low (LW) juvenile body weight, reared in cages and floor pens as line-separate (S) and line-intermingled (1) flocks. There were three trials. Percentages of chicks eating and drinking were similar or greater in I than S flocks. There were no trial by I-S interactions for these behaviors at 3, 14, and 28 days of age. On Day 7, however, these interactions were significant and possible causes for them are presented. Line HW chicks reared in cages were heavier in I than S flocks, whereas, no influence on body weight was evident under floor rearing for HW or for LW chicks. Mortality for HW chicks was very low. Anorexia has been reported in the LW line and death from starvation was greater in that line for S than I flocks in cages. This difference in mortality was not observed in floor pens. The results of this research suggest that ingestive behavior, livability, and growth may be influenced by intermingling chicks from genetic lines that differ in eating behaviors. The degree of influence, however, is not independent of age, housing environments, and genetic stock.