We observed the feather of peacock under foldscope and learned about the cells of rachis. The feather consist of  Vane, Rachis, Barbs and Hollow shafts. The rachis contains pith, which is composed of air-filled keratinised epithelial cells surrounded by a solid keratinised outer cortex. … Barbs: The series of branches fused to the rachis , constituting the major surface area of the feather . Barb ridges are folds of the original epidermis of the embryonic feather germ in which the basal–apical polarity of epidermal cells is upset. … The formation of branching barbules occurs by the presence of barb vane ridge cells that function as spacers between barbule cells .