Abstract: To study the law of growth and development of Bashang long\|tail chicken, the nonlinear curves of Logistic model, Gompertz model, and Von Bertalanffy model were used to fit the growth dynamic. The results showed that the residual sum of squares of Gompertz and Von Bertalanffy models were smaller and their fitness degrees (R2) were above 0997. The Gompertz model had the best effect on fitting with the growth curve. The Gompertz model equation of body weight was Y=2015524e-4218exp(-0146t) for male and Y=1396131e-3849exp(-0155t) for female, respectively. The maximum applicable adult body weight of cock was 2 015524 g which was larger than that of the hen (1 396131 g), while the inflection point age of the former (9859 weeks) was later than that of the latter (8696 weeks), and critical body weight of the former (741470 g) was larger than that of the latter (513608 g) too.

Key words: Bashang long\, tail chicken, growth curve, Logistic, Gompertz, Von Bertalanffy