Metabolic Changes in Growing Chickens

Abstract

Data are reported on oxygen consumption in relation to body weight, age, and surface area of Rhode Island Red chickens from hatching to 6 months of age in males and to 13 months of age in females. Attention is directed to an apparent parallelism during the first 2 months after hatching, between metabolism per day, expressed in Calories per square meter, and growth per day, expressed in grams per square meter. The resting but non-fasting heat production at thermoneutrality increased during this critical period from about 750 Cal. at hatching to a maximum of 1,250 to 1,300 Cal. at about 30 days, and thereafter decreased to 900 Cal. at 60 days. Daily growth rate per square meter similarly increased to a maximum of approximately 370 gm. at about 25 days, and thereafter decreased. After 2 months of age, the non-fasting heat production in the females averaged about 900 Cal. as compared to 750 Cal. after 24-hour fasts. Higher values were obtained for the males.