Three Gallus domesticus cocks were reared separately in a climatic chamber at 22 degrees C, with lights on at 0600 and off at 1800 h. Food and water were available at all times. At noontime, one bird was handled for the purpose of taking cloacal, comb, and foot temperatures every 3 min for 18 min. Repeated handling produced a fever characterized by a mean rise in core temperature from 41.1 +/- 0.3 degrees C to 41.6 +/- 0.3 degrees C and an initial peripheral vasoconstriction, as shown by a drop in skin temperatures. Maximum core temperature was only 39.9 +/- 0.2 degrees C when the birds received intraperitoneal salicylate 1 h before handling. It is concluded that handling causes a fever in birds. The birds were equipped with an electrocardiogram radio transmitter, and their heart rates were recorded at a distance. When simply touched by an experimenter, the birds' mean heart rate rose from 198 +/- 6 to 249 +/- 15 beats/min. We conclude that fever and tachycardia might indicate the existence of emotion in birds.