Thermal correlates of tonic immobility and social isolation in chickens.

Previous research has shown that core temperature in chickens drops following the induction of tonic immobility (TI), while hyperthermic trends emerge shortly after response termination. Other research has shown that birds placed in social isolation also become hyperthermic. Since testing for TI is usually carried out while animals are isolated, there is a question as to whether the hyperthermic reaction after the termination of TI has any relation to the episode of TI itself as opposed to being due to the effects of social isolation per se. The present series of studies found that although social isolation did produce significantly longer durations of TI and that the core temperature of isolated birds was affected, when core temperatures were independently raised or lowered, no significant differences were found in TI durations relative to controls. Additionally, in contrast to core temperature changes, shank temperature showed the opposite effect, while another peripheral temperature measure, wing temperature, remained stable.