My Barred Rock had a serious wing injury a year ago, after being chased into a tree by what I can only assume was a cat. She hung there, caught by her wing, until my Husband came home from work. The wing was dragging on the ground, skin was a little torn, and she started pecking on it. Just talking with a veterinarian friend she mentioned that the pecking could be a sign that there was a damaged nerve which was creating a "pins and needles" type sensation. Anyway, the whole thing bruised and turned greenish in about a day and I was very unsure what to do. Folks on here recommended a variety of solutions- the two most helpful being to cut a stocking or pantyhose into a short tube and use that to hold the wing by sliding over the birds whole body- and then the type of bandage that the previous poster mentioned. I went to the vet's office and bought the bandage. I wrapped it into a neutral position next to the body- not too loose, not too tight, with the other wing free. For the first day I kept her confined to a very small crate, with some good treats, so that she wouldn't be as able to move freely and pull of the bandage, and so the other chickens wouldn't peck at it/her. After a day I realized the crating was stressing her out, so I put her back in the main coop and watched to make sure nobody was being mean to her. It went fine, I just had to catch her and re-bandage daily because the bandage would get dirty and she would sometimes get part of it off. After about a week or so I was able to remove the bandage.
She now holds her wing in a normal position and it pretty much healed. I don't see the Barred Rocks flap much, so I don't know if she is really able to or not- but her gait is normal, laying is normal, wing is carried in normal spot. The bad side is that she used to like to be handled and ever since this incident she is pretty stand-offish.
Good luck!