Influence of ambient temperature on feeding activity parameters and digestive function in domestic fowls.

In order to better understand the way in which domestic fowls regulate their food intake at different ambient temperatures, measurements were made of feeding activity parameters, drinking, rate of food passage, apparent digestibility and gut dimensions of immature female fowls acclimated to cool (8 degrees C), moderate (20 degrees C) and warm (32 degrees C) environments. At 8 degrees C birds had longer (p less than 0.05) intervals between meals, ate larger meals, ate faster within meals and digested their food more efficiently than at 20 degrees C. At 32 degrees C they ate less food per day, drank more water, had a higher water/food intake ratio, ate slower within meals, had a slower rate of food passage, and had smaller proventriculi, gizzards and caeca than at 20 degrees C. It is concluded that differences in daily food intake between temperatures are associated more closely with differences in meal size and rate of eating within meals than with differences in meal frequency. Effects of temperature on behavioural thermoregulation, drinking and rate of food passage all influence patterns of feeding activity shown.