Effects of ambient temperature and restricted feeding on the growth of feathers in growing turkeys.

1. Male turkeys were reared to 6 weeks of age at 15 degrees C and 26 degrees C and fed ad libitum or restricted to 0.5 of the body weight of birds fed ad libitum. Basal metabolic rate was determined by indirect calorimetry at an ambient temperature of 20 degrees C. 2. Turkeys at 15 degrees C were lighter than those kept at 26 degrees C. Feather lengths and weight were similar in both groups. Fasting heat production corrected for both metabolic body size and activity was greater in turkeys reared at 15 degrees C than those at 26 degrees C. 3. Cranial breast feathers were significantly longer in restricted birds than in those fed ad libitum in contrast to a proportional decrease in the lengths of other feathers of 0.1 to 0.3. Feather weight as a proportion of body weight was 0.072 in restricted turkeys compared with 0.046 in birds fed ad libitum. There was no difference in basal metabolic rate between ad libitum and restricted turkeys. 4. It was concluded that feather growth was maintained in preference to body and muscle growth and that rearing birds at 15 degrees C did not improve breast feather cover. It is suggested that the growth of breast feathers in turkeys fed ad libitum is impaired.