What is the deal with the feathering on Tyrannosaurus rex? I can't really find anything reliable online, except for Mark Witton's blogpost about the topic, but some renowned paleoartists like Fabrizio de Rossi's recent "All Hail the Queen" artwork. So was T. rex fully scaly, did it have a few bristles on the back of the neck and on the trailing edge of the arms? I think that adults had some bristles while juveniles had much more feathering. What is the current theory?