Feather is an important economic trait of poultry, and growth and development state of feathers plays an important role in the economic value of poultry. Dermal fibroblasts are required for structural integrity of the skin and for feather follicle development. How FOXO3 affects feather follicle development as skin tissues change during goose embryo (Anser cygnoides) development and growth is not well understood. Here, we demonstrate that in vitro culture of single feathers and skin tissue results in changes in feather morphological structure by adding drugs to the culture medium that affect FOXO3 expression. We used feather follicles to show that during growth, the root location of feathers, the dermis layer, affects cell proliferation and apoptosis and regulates the expression of major genes in the Wingless-types/beta-catenin (Wnt/β-catenin) signaling pathway through the activity of FOXO3 in dermal fibroblasts. Feathers and dorsal skin tissues develop the correct structure, but feather length and width and feather follicle diameter change significantly (p < 0.05) without significant changes in feather follicle density (p > 0.05). Transfected dermal fibroblasts also showed that FOXO3 affected the formation and development of feather follicles in the embryonic stage by regulating the Wnt/β-catenin signaling pathway. Therefore, this study reveals the critical role of dermal fibroblast-FOXO3-induced Wnt/β-catenin signaling in promoting the formation and development of embryonic feather follicles.