The feather growth process of Cherry valley duck embryo Ⅰ: Nonlinear model fitting analysis and feather follicle development detection.

Feathers are defining characteristics of birds, and the specific feather structure of waterfowl contributes to their economic value. In recent years, feather quality has become one of the conventional evaluation indexes of meat ducks. However, a systematic exploration of feather growth patterns in meat ducks is still lacking, and the optimal time points for regulation remain unclear. In this study, Cherry Valley ducks at 11 different embryonic stages were selected to investigate feather growth patterns and feather follicle development procedure. Logistic, Bertalanffy, and Gompertz models were applied for nonlinear regression analysis. Results showed .All three curve models effectively captured the dynamics of feather growth in Cherry Valley ducks during the embryonic period, with goodness-of-fit values exceeding 0.94. Among these models, the Gompertz curve provided the best fit for the feather mass, and the Bertalanffy curve for the feather length in Cherry Valley ducks during embryonic development. Furthermore, embryonic age (E) 18 was identified as a pivotal turning point in feather development. The study also observed that both the width and depth of feather follicles increased with advancing embryonic age. Additionally, the diameters and densities of primary and secondary feather follicles exhibited a positive correlation with embryonic age. The application of mathematical models to characterize the developmental patterns of feathers serves as a useful tool for managing feather growth through nutrition and husbandry practices. These findings offer valuable insights for studying the regulation of feather development and addressing feather-related challenges in poultry production.