Evaluation of the Effects of Variety and Hatch on Body Weight and Mathematical Description of the Growth Curve Using the Gompertz Model in Guinea Fowl (Numida meleagris)

This study was conducted to investigate the growth pattern and evaluate the effects of phenotype and hatch order on body weight in guinea fowl chicks from 15 to 210 days of age. The chicks were obtained from two phenotypes, gray and bluish-gray, and from four consecutive hatches produced by native breeding stock. The chicks were reared under identical management and nutritional conditions, and live body weight was individually recorded at two-week intervals. Individual data from 250 chicks were analyzed using analysis of variance (ANOVA) and Duncan’s multiple range test in SPSS software. The growth curve was plotted based on mean body weight, the Gompertz model was fitted, and Pearson’s correlation coefficients between body weight at different ages and body weight at 210 days of age were calculated. The results showed that body weight growth in guinea fowl followed a sigmoidal pattern. Mean body weight increased from 68.51 g at 15 days of age to 981.94 g at 120 days and 1,289.10 g at 210 days of age. The highest growth rate was observed approximately between 30 and 135 days of age, after which the rate of weight gain decreased markedly after approximately 150 days. Fitting the Gompertz model estimated the asymptotic mature weight at approximately 1,296.87 g. Furthermore, the correlation coefficient between body weight at different ages and body weight at 210 days increased from 0.130 at 15 days to 0.692 at 135 days of age, indicating that body weight at approximately 135 days of age could serve as a suitable indicator for predicting final body weight. Based on these findings, the period from 30 to 135 days of age represents the main phase of rapid growth, while the period from approximately 120 to 150 days is particularly important in terms of weight gain and economic management.