Every situation is different and must be dealt with accordingly, so here is our experience. About a month ago Eva went out to open the grow-out coop in the morning and found Blondie,our 10 week old Buff Brahma hanging upside-down with her leg caught between the wall and the board the roost pole was mounted to. She was barely alive and it was obvious she was severely injured with possible leg/hip damage. While many would have said to cull her she is our favorite of this group so we decided to save her if we could. She was barely responsive when we got to her!
Here is what we did.
We brought her inside and started dribbling sugar water on her beak to get her drinking while holding her to get her body temp back up. We fashioned a bed in a cheese box for daytime and a milk crate just big enough for her to lay in for nights. Once she was more responsive we continued to give her water and when she showed interest in food we crushed baby aspirin into powder and gave it to her on treats twice a day. The dosage was a guess but was about 1/4 of a baby aspirin every 12 hours, not as much for pain as it was to help with the inflammation. We gave that for about a week.
With everything posted about chickens that are away from the flock having to start over in the pecking order we started taking her out to the baby coop for a while each day,first for an hour and as she started getting better extended the time a little each day. After a couple of days she had gotten to where she could stand on the leg some and hobble on one leg but mostly just laid with her mates in the grass. When she was in the house she sat in her cheese box on the counter or on the desk by the computer(it's neat to note she did seem to enjoy watching the computer screen,esp. with games or bright colors).
Slowly she started regaining use of the injured leg/hip,first standing on it for longer periods,then walking short distances. Sometimes she would wave the injured leg,trying to get it do what she wanted several times before it would make the step. When outside with her mates she would follow them across the yard,although much slower. After a couple of weeks we returned her to the the baby coop full-time and she continued to get better.
Now,a month later she can almost keep up with the other girls and we have intergrated all the babies into the main coop. We even made a low roost pole for Blondie but to our surprise she was the first of the babies to roost on the high roosts!.
This process was a lot of work and might not be for everyone but if you have a favorite that gets injured you can do a lot for them. Our methods were hit-or-miss, a mix of what we learned here on BYC,from a couple of books and from our experience with dogs over the years,mixed with common-sense and a good bit of luck.
Larry