Doesn't look like any I have ever seen with mange. Last one I saw that had mange was in really sorry shape. He stood watching us at work for hours on afternoon. I thought he would be dead by days end and maybe he did die that day but if he did he walked off and hid somewhere. Sorriest looking animal I ever have seen. I actually felt sorry for him but was in city limits so even if I had a firearm to put him out of his misery I could not have. He had no fur from the front legs back. Just skin, the fur around his chest and neck looked like a Lions mane. I was to within 10 yards of him several times and he did not move, he could barely lift his head and when he did his eyes were so cloudy I don't know that he could even see me.........I think your had an accident of some kind and was just having a real hard time making a living. With that back leg like it is and cold winter having set in, hunting would not be easy at all, he was probably starving. I am sure you did him a favour!