| The effects of environmental temperature, dietary energy, housing system, time of feeding and day length on core body temperature (CBT) dynamics in broiler breeder females was studied in a series of experiments. Environmental temperatures within the range of 15 to 27°C resulted in a CBT of 39.8 to 42.1°C. Environmental temperature affected feed intake, growth, CBT dynamics and efficiency in pullets, but not the egg production, egg weight or feed efficiency in hens. Low energy diet-fed hens laid heavier eggs. Free-run and caged hens had similar egg production but free-run hens produced heavier eggs. However, free-run hens required by 17.2% more energy than caged hens, likely to support activity level. Feeding twice per day delayed oviposition relative to morning-fed hens. Photoperiod effects were seen in diurnal CBT patterns. Peak CBT occurred soon after feeding and could be shifted by changing feeding time, and may have potential for heat stress mitigation. |
