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.

As light as a feather

Hair, feathers, and scales: An evolutionary tale

Getting to the root of scales, feather and hair: As deep as odontodes? - Dhouailly - 2019 - Experimental Dermatology - Wiley Online Library

Did Dinosaurs Turn into Birds?

30 Extraordinarily Beautiful Birds You Might Not Have Heard About

Everything You Need To Know About Feathers

Dinosaurs and the evolution of feathers

Feathers, Hair or Scales: Not Much Difference

Scales or feathers? It all comes down to a few genes