1. By the application of the mold method the individual surface area of 17 chickens of approximately one month of age were determined and formulae evolved for the prediction of the surface area. The value for K in the Meeh formula was found to be 11•2, while by the method of least squares a formula equivalent to S = 36•31 W ⁴⁵⁷ was obtained.
2. The basal heat production of one-month-old chickens, when expressed per square meter of body surface, was found to be 891 calories per day. If the formula of Mitchell for estimating- the surface area is applied, the basal heat production becomes 1,085 calories per day.
3. It appears that the highest basal metabolism in chickens is reached between 3½ to 4½weeks.