Oh you didn't know? this was resolved awhile ago, T-Rex did not have feathers and neither did any of the other North American dinosaurs of that size and type. Carnotaurus, Albertosaurus, Allosaurus, etc. they all had leathery or reptile like skinI gotta be honest it does disappoint me that most Dinos apparently looked less like badass dragons and more like roided up turkeys.
Please let T-Rex at least stay a reptile God.
Only a single gay chinese dinosaur did, and you know what? Fuck china it could be a fake because they have a history of faking shit and erasing/destroying stuff (they hid caucasian mummies that were found in China because the government thought that having white people appear in china thousands of years ago would destroy their modern day heritage).
Also i want to mention that Ostriches and their relatives like Cassowaries used to be smaller flighted birds before they evolved into what they are today. Their ancestors were feathered small birds and the lineage lost the ability of flight around the world multiple times. They were not Gallimimuses or Troodons. Birds(or Reverse Birds/Opposite Birds named for their switched shoulder structure) appeared towards the end of the cretacious peroid alonside dinosaurs, they didn't come after the great extinction.