In the time travel western I'm writing, outlaws ride utahraptors. They're the size of horses, and. they. have. feathers. (Sorry, Jurassic Park; you've always been my favorite movie, but your "velociraptors" leave a lot to be desired in the realism department. Like I can talk; my technicolor raptors wear saddles and attack stagecoaches... but at least they have feathers).
This lovely lady is River, the mount of the as yet unnamed outlaw leader. I opted against full, wing-like arm feathers as I like the flowy look of the feathers on her head and tail (and I don't have the skills to make it look nice that way).
I traced the outline from this diagram on Wikipedia.