The current study was conducted to investigate the effect of short-term selection for 4 wk BW (BW) on the performance of divergent lines of Japanese quail and their crosses. The mean of BW at 1, 2, 3, and 4 wk of age in each group (2 lines and their crosses) were compared to investigate the maternal and heterosis effects. There were significant differences (P < 0.05) between the mean of BW in each group. Moreover, the reciprocal effect (maternal effect) was significant (P < 0.05) for all BW measured at different ages except for 4-wk BW in males and 3- and 4-wk BW in females. However, the effect of heterosis was not significant for all BW measured. The description of growth curves in each group and control line was compared with 3 mathematical models (Gompertz, logistic, and Richard). Based on the error variance, the logistic model described the growth pattern of Japanese quail and their crosses better than other models.