Jones, R. B., Williams, J. B. 1992. Responses of pair-housed male and female domestic chicks to the removal of a companion. Applied Animal Behaviour Science 32, 375-380.

Male and female domestic chicks were housed in same-sex pairs until they were tested at 11 days of age. One chick was then removed from each established pair. .. Social separation induced an overall increase in circulating corticosterone concentrations, thus illustrating its stressful properties. No sex difference was found.