Abstract: The study aimed to study the weekly changes of body weight and body composition of Wenchang chickens, and establish the empirical growth model to provide scientific basis for efficient breeding of Wenchang chickens. A total of 300 healthy 1-day-old female chicks with similar body weight were randomly divided into 6 replicates and fed conventionally until 119 days of age. The body weight and body composition of Wenchang chickens were measured weekly. The results showed that the body weight, carcass weight, feather weight, body protein weight and body fat weight of Wenchang chickens increased significantly with the increase of week age (P<0.001). Four nonlinear function formulas, Gompertz, Von Bertalanffy, Logistic and Richards, were used to fit the growth curves of body weight, body protein and body fat of Wenchang chicken, respectively. According to the determination coefficient (R²), mean square error, Akaike information criterion and residual sum of squares of regression models, it is found that Gompertz model has the highest degree of fit. The growth models of body weight, carcass, feather, body protein and body fat of Wenchang chickens were established using Gompertz model. Except for the feather moisture weight, the R² of the other component models was close to or exceeded 0.99. The mature weight of body weight, body protein and body fat were 2 382 g, 696.8 g and 1 037.1 g, respectively. The relative maturity rates were 0.023 2, 0.017 4 and 0.017 8, respectively. The Gompertz model can be used to predict the body weight and body composition weight of Wenchang chickens at different days of age. These models and their calculus formulas are helpful for genetic selection and production decision-making of Wenchang chickens, and also provide a basis for predicting the daily energy and amino acid requirements of Wenchang chickens in the future.

Key words: Wenchang chicken, growth stage, Gompertz model, prediction model