Social reinstatement and open-field testing in chickens

Based on a model which holds that open-field behavior represents a combination of predator evasion tactics and attempts to reinstate contact with conspecifics, five experiments were conducted with chickens to assess the effects on them of social separation in response to being placed in a novel enclosure. As a means of independently demonstrating reinstatement tendencies, it was shown that birds would run faster down a straight alley if the goalbox contained one or more conspecifics than if it was empty or contained a guinea pig. For birds tested in pairs, the effects were different, depending on whether they had been reared in pairs or in larger groups. On the other hand, although chicks froze and remained silent longer in pairs, they seemed to be relatively insensitive to whether the pair member was a cagemate or a stranger. Finally, as predicted, reinstatement tendencies diminished and predator evasion tactics predominated with increasing age.