Comment by glauque

Indeed, and a fairly recent discovery among Velociraptors.

> The feathers of the flightless Velociraptor may have been used for display, for covering their nests while brooding, or for added speed and thrust when running up inclined slopes.

https://en.wikipedia.org/wiki/Velociraptor#Feathers

http://science.sciencemag.org/content/317/5845/1721