The epidermis divides and a new inner epidermal layer forms. The 2 epidermal layers separate and the outer one is lost as a whole piece or in patches. Turtles and crocs have scale-like plates called scutes. The scales of snakes and lizards are also referred to as scutes. There are a few scent glands found in patches on various reptiles.
Birds have mostly thin skin with little keratin.
The feathers are keratinized as is the beak. The legs have thick scales. The uropygial gland is used to produce oil to preen the feathers. The typical feather is a contour feather. It functions in flight.