I just hopped on here to say a few things: First, chickens can survive some amazing injuries so as far as injuries go I usually try to treat before euthanizing. I do euthanize when appropriate.
Second, we have a major bear problem. Once they find a source of food they WILL come back. I didn't read every page so I don't know every detail, but if you haven't started bear proofing, you need to NOW. They tend to hit up the same place every 2-4 weeks as they cover a large territory. I have had my coop torn apart on three occasions from the same bear. I've lost birds to him. I've also had one survive being hit by his paw, slammed into the wall, dislocating her wing and breaking possibly the wing and some ribs. She also had a lot of missing feathers and some small puncture wounds. She showed a strong will to survive so I treated her and a year later, she is still running around, albeit a bit on the lopsided side. Her entire right side is droopy.
To bear proof we set up a powerful electric fence. I'm a young woman, never had to do anything like that myself, and BYC and Google taught me all I needed to know. I installed the system myself. The summer was dry so I had to water the ground regularly. Without a camera I do not know how effective this really was since he came back twice after setting up the fence. I even rubbed bacon grease on it to encourage him to make contact with sniffing. Finally I had to set up unwelcome mats. These are large pieces of plywood with nails sticking straight up. Every single night I lay the mats out surrounding the coop. Thus far, the bear has never gotten into the coop since using the mats.