"billed dinosaurs, horned dinosaurs and armoured dinosaurs did not have feathers because we have lots of skin impressions of these animals that clearly show they had scaly coverings" [1]<p>There is no evidence for example that protoceratops, whose skulls are pictured in the article, had feathers.<p>Non-avian theropods had feathers, but even then were not necessarily covered with them, it could be a few feathers under the arms. We are talking about species over a 200 million year time period.<p>[1] <a href="https://www.nhm.ac.uk/discover/news/2020/march/the-first-dinosaurs-probably-didn-t-have-feathers.html" rel="nofollow">https://www.nhm.ac.uk/discover/news/2020/march/the-first-din...</a>