Thermal preferences of chicks brooded at different air temperatures

1. The thermal preferences of small flocks of 400 chicks brooded under radiant heaters were determined at air temperatures of 21, 24 and 27 degrees C from observations of behavioural thermoregulation. 2. At 1 d of age the upper limits of the preferred black bulb temperature increased with air temperature. Preferences for radiant temperature declined with air temperature. 3. Compensation for cold air temperature was imperfect because the chicks avoided zones of high radiant flux. The maximum tolerable radiant temperature was approximately 50 degrees C. 4. Radiant heaters are preferable to convectors in poultry husbandry because the inherent lack of spatial homogeneity in thermal environments ensures that chicks can satisfy their individual thermal preferences.