Well soldiers just love a feather in the caps! Ostrich feathers were popular some units used peacock feathers. Most of the ostrich feathers on the Union hats were gone after a shot time of wear.
Forrest's dress hat had a small feather in it but his usual hat was a battered (and shot up) faded black beaver hat with just the braid around the base. After the war, a visitor mentioned Forrest met him at the door wearing a wide brimmed straw hat, which seemed to disturb the visitor. Well, back to being a farmer!
It does appear that many of the Native American soldiers in the War west seems to have loved peacock feathers. I would suspect that every peacock in the area ended up being bald.