Behavioural and growth responses of broiler chickens to dietary water content and climatic variables

1. The behavioural responses and growth of broiler chickens were investigated over three seasons using two wet mashes with food:water ratios of 2:1 (HW) and 3:1 (MW).

2. Wet mashes fed in the hot dry season caused significantly lower rates of panting, a major thermoregulatory behaviour. This may be an indication of increased comfort in hot dry conditions for birds fed wet mashes.

3. Feeding activities of birds fed dry and wet rations respectively increased and decreased with decrease in seasonal temperature. The peaks of both feeding activity and consumption in the cool‐dry season were attained by birds fed dry diets and in the hot dry season by those fed wet mashes.

4. Diurnal distributions of food and water intakes were more even in the hot dry season for those fed wet mashes. This may again suggest a higher degree of comfort on the hot dry season when birds are fed wet mashes.

5. In the hot dry season, 60% of birds preferred wet mashes, whereas 80% of birds preferred dry meal in the cool dry season. This may be attributable to the lower temperature of wet mashes.

6. Similar patterns in feeding activity, food consumption and daily weight gain occurred in response to dietary presentation and season.

7. Feeding of dry meal under cool dry conditions and wet mashes in the hot season may be advantageous. Irrespective of season, water temperature may have to be raised to about 30°C before addition to meals for chicks under brooding. This may be necessary as preliminary investigations in this laboratory indicate that food temperatures below 22°C may at the brooding stage discourage food intake and activities.