Birds have a thin kind of skin underneath their feathers. Their skin is similar to mammals but much more delicate.
Both have spines (vertebrates) and skin (underneath the fur or feathers).
They don't, they have feathers on top of their skin.
Birds have feathers on their skin
The body covering on birds is considered the feathers, or plumage. Birds do have skin under their feathers, but their feathers are the outermost covering that protects their bodies.
Feathers
Down feathers are located underneath contour feathers. They are fluffy and provide insulation to help birds regulate their body temperature.
Normal skin, with feathers attached to it! :)
Toucans are mostly covered with feathers, but underneath that is skin.
Down feathers.
Quails are birds. They have feathers.
Humans do not have feathers because we are mammals, not birds. Feathers are unique to birds and are used for flight, insulation, and display purposes. Humans have evolved hair instead of feathers to regulate body temperature and protect the skin.