A general mathematical description of the feed utilization was aimed in this study. Three different plumage colour lines of Japanese quail were raised to collect their growth and feed consumption data at three-day intervals up to 48 days of age. The model equation is in the linear fashion with two parameters, which of both have biological meanings. The regression coefficient is the measure of the net feed need to produce one unit live quail weight while the intercept coefficient is the measure of the net feed need just for supporting the daily activities of quail. The regression coefficient values have ranged from 0.7430 to 1.1327 g feed/g liveweight gain. The regression coefficient for brown quail differs from the one for wild quail. The intercept coefficient has ranged from 0.1238 to 0.1342 g feed/g quail weight/day. The proposed linear model can be used together with the growth model to perform the computer simulation of quail raising for developing economic farming practices.