I've used some aloe vera gel on a hen that had been attacked by dog..It was more open than on the picture. I was cleaning it twice daily with some natural marseille soap, and then drying it with a gauze and applying aloe vera gel...She got better within a month. However, I had a hen attacked by a fox and the whole skin from the back down to the leg was missing( the muscles were naked), and she had a puncture wound underneath the wing that got infected. The vet opened the puncture wound, to clean it, got her some pain killer, antibiotic, and silverdene cream....It was not healing, but was not getting worse.and the infection was under control. So the vet tried some golden powder that I was mixing with aloe vera gel, and it healed despite all the odds ( the gap between both sides of the skin was huge). It took about 4 or 5 months to heal. We were tube feeding her with some harrison bird recovery food.
Chickens are usually good healers for wounds like that.