Visual lateralisation and development of spatial and social spacing behaviour of chicks

We tested the hypothesis that domestic chicks incubated in the light and provided with experience of moving out of sight of each other (occlusion experience) during rearing would have better spatial cognitive abilities than control chicks. Ninety-six chicks were incubated in the light or dark and half the chicks had the opportunity to move behind opaque barriers from 10-12 days of age and the remainder we provided with identically-sized transparent screens as a control. Chicks were tested in a detour test, a rotated floor test and their dispersal was observed in a large pen. Chicks reared with opaque screens used distal cues significantly more when searching for their companion in a rotated floor test (P=0.042) and light incubated chicks tended to make a choice in less time than dark incubated chicks in this test (P=0.089). There were no significant differences in the time taken for the chicks to solve the detour test depending on the chicks' occlusion experience or incubation environment, possible because the ability of chicks to use the sounds from the social goal masked any differences in orientation ability. Incubation and occlusion treatments were not found to have a significant effect on dispersal. We conclude that although minor manipulation of the incubation and rearing environment affect the use of spatial information and ease of processing of conflicting cues in chicks, it is unclear whether these changes in behavioural phenotype translate to actual advantages in movement, dispersal and welfare of chickens in loose-housed commercial systems.