The relationship between starvation heat production (SHP) in kJ/d and body weight (W) in kg for the domestic fowl was examined by compiling calorimetric data on 78 immature and 222 mature fowls. Linear regression analyses were performed after transformation of the data to a logarithmic scale (base = 10). The derived relationship (re-transformed) for mature birds was found to be: SHP = 406 W0.602 The weight exponent (b) was significantly (P less than 0.01) different to the value of 0.75 normally used for mature birds.