Birds develop feathers the same way we develop hair and teeth •

The hexagonal patterning of bird feather growth relies the same signaling pathway used to form hair, teeth, and scales in mammals, fish, and reptiles.

Everything You Need To Know About Feathers

The Parts of a Feather and How Feathers Work

Sprouting feathers and lost teeth: scientists map the evolution of

Everything You Need To Know About Feathers

Microscopic feather features reveal fossil birds' colors and

Human hair, bird feathers came from reptile scales, Science

We finally know when birds lost their teeth - The Washington Post

Everything You Need To Know About Feathers

Birds of a feather: An annual summertime bird banding project

Feathers Zoology, Division of Birds