Latency to traverse a T-maze at 2 days of age and later adrenocortical responses to an acute stressor in domestic chicks

Latencies to escape from a T-maze, and thereby reinstate visual contact wit h conspecifics, were measured in broiler chicks at 2 days of age. Chicks we re assigned to high- (HP) or low- (LP) performance categories if their esca pe latencies fell below 25 s or above 75 s, respectively. These chicks were then housed socially in 10 same-category groups (5 KP, 5 LP), each compris ing eight birds. At 15 days of age, one chick was taken from each of two ra ndomly selected cages (1 HP, 1 LP) and immediately bled (undisturbed contro ls). At the same time, another chick was taken from each of these boxes and immersed up to its neck in warm water (partial water immersion, PWI) for 1 5 min before blood was collected. All chicks were sexed after bleeding. The re were no differences between the plasma corticosterone (CS) levels of und isturbed (control) HP and LP chicks. Exposure to PWI significantly increase d circulating CS levels, and this elevation was more pronounced in LP than in HP chicks. Male chicks also showed higher stress-induced adrenocortical responses than did females. The present findings suggest that the T-maze re sponses of young chicks might predict their later adrenocortical responses to a known stressor. This relationship is discussed in terms of individual differences in fearfulness, ability to cope with challenge, and/or stress s usceptibility. (C) 1999 Elsevier Science Inc.