The below poem is one I found in 'Structures' by J. E. Gordon. He explains how pterodactyls and bats were succeeded in evolution by birds with the use of feathers and then asks why don't we use feathers. There must have been a few fun moments when he worked for the RAF and asked his superiors why his planes remain like pterodactyls and don't use feathers. The answer is that feathers provide higher manoeverability. Take for example a plane or a helicopter and add trees, they are not able to fly through trees but birds are able to live in trees and that shows how their wings can adapt to the air and allow them to fly through things, avoiding damage. Feathers provide protection against bumps, they were used by the Japanese to creat armour - they are very good at preventing damage from swords. Feathers are extremely sensitive, nobody really understands the fracture mechanics of a feather. Apparently the US Army lives on chickens and there is a mountain of feathers somewhere - wouldn't it be great to put them to good use.