An interesting question. Birds’ feathers and scutes (the large scales on their legs) and crocodiles’ scutes are all made up of very similar proteins. Dinosaurs have scutes. The solid nature of a scute might be a secondary development. More dinosaur fossils are being found with the carbon traces of feathers around them—including fossils of the ancestors of Tyrannosaurus rex.
Feathers didn’t evolve for flight, just as mouths didn’t evolve for talking. In both cases, an existing structure was put to a new use. We already know that lungs and swim bladders have evolved from and into each other in different groups of animals as conditions changed. It wouldn’t be a shocking new development if feathers and scutes did the same. See feathers, scutes, and the origin of birds by Jeff Poling.
Please note that the link is not to breaking news: it is to an article from 1996, by Jeff Poling, summarizing even earlier research.