I saw this poor squirrel today, and tried to catch it to take to the vet, but even though he had a bad foot, he easily out ran me. Not sure how his foot got injured, but it looked like it was gone or close to at least. Hopefully it wasn't a person who did it, while i'm sad it was hurt, if it was other wildlife, it's more understandable. He would eat, and when he put is back right foot down, he could feel it hurting, and would shake it out back and up a lot.
Once when i saw a rabbit with a bad leg, i asked the vet what i should do. She told me that if it the wild animal can get away from me, it should be able to get away from predators and not to worry about it so much. Also that if it's eating, it's not fatally injured or sick. I feel less bad about wildlife doing what they need to survive, but when it comes to people, they can be cruel for no good reason. So hopefully it was an accident or such that caused this.