Early T-maze behaviour and subsequent growth in commercial broiler flocks

1. Two batches of 2000 mixed-sex broiler chicks were obtained, one in summe r and one in winter. Each flock was housed on the floor at a commercial far m. At 2 or 3 d of age, the latencies to escape from a T-maze were measured in 1044 and 1180 chicks in the summer and winter flocks, respectively. Chic ks were assigned to high (HP), moderate (MP) or low (LP) performance catego ries if their escape latencies were below 40 s, between 40 to 90 s, or abov e 90 s, respectively. 2. Ninety male and 90 female chicks from each of the 3 categories were weig hed when they were 3 d old. The birds then remained undisturbed, apart from routine maintenance, until similar numbers were weighed at 49 d of age. So me birds may have been weighed at both ages. 3. Body weights were higher in males than females and higher in the winter than summer flock at 3 d of age. 4. Significant main effects of chick category as well as gender and season were found at 49 d of age. There were no significant interactions. As expec ted, 49-d body weights were higher in males than females and in the flock r eared in winter than in summer. 5. HP chicks (those that showed rapid escape from the T-maze at 3 d) were a lso significantly heavier at 49 d than their LP counterparts, with MB chick s occupying an intermediate position. This suggests that early performance in a T-maze test is positively associated with subsequent growth. Furthermo re, this relationship was apparent in each of the 2 flocks. 6. Given this positive association, we suggest that this simple, rapid and non-invasive behavioural test could be a useful selection criterion for fut ure breeding programmes.