With a BB gun? My father has been shooting squirrels with BB guns since he moved into his new house(about 5 years). Never left any blood or anything. Maybe with a bb gun rifle(that depends on where you shoot em, obviously headshots do more damage than hitting one in the leg), but with a BB handgun i have never seen any fall, or limp even. As for the skin, it might be. I don't remember, as my squirrel/coon hunting days are long behind me.