1. 1.|The maximum thermoregulatory increase in heat production (HP) of defeathered laying hens exceeded that of the feathered ones at thermoneutral temperatures by 238%. 2. 2.|The HP of laying hens is an appropriate physiological parameter to calculate the total effective ambient temperature (Ta). 3. 3.|The cold sensitivity of the thermoregulatory system in laying hens was determined by three different methods (a) from the relationships between Ta and HP in well feathered birds in the range 5 to 25°C; (b) fromm the relationships between Ta and HP in defeathered hens in range 20 to 40°C; (c) from the relationships between Ta and HP in the total effective ambient temperature range (EAT1)(-15 to -18°C) and was found to be about -3,2 W kg-1. © 1986.
Nichelmann, M., Baranyiová, E., & Goll;, R. (1986). Influence of feather cover on heat balance in laying hens (Gallus domesticus). Journal of Thermal Biology, 11(2), 121–126. https://doi.org/10.1016/0306-4565(86)90032-X