Aw, poor guy. It does sound like his life would be a bit improved by a trim. There isn't really a lot to trimming feathers. You can't hurt the bird as long as you stay away from the very base of the feather, so you can trim to whatever length you want.
The trick is holding the bird still for the proceedure. I've always had a lot of luck with waiting till all the birds are roosting for the evening just after dark. You can pull your rooster out without much fuss at that point, and wrap him in a towel with his feet sticking out. This keeps his eyes covered and his wings gently pinned, which helps IMMENSELY. Just be sure not to wrap too tight, or too loose.
Just bring him inside for a trim over the garbage can, take him back outside, unwrap and plop him back on the roost. He'll have a cool alien abduction story to tell the others in the morning.