I've sent alot of raccoons to heaven and I don't believe that all that kicking and jumping around they do after you shoot them is painful if it makes you feel any better. It is just the nerves in the brain and spine going whaco, I don't think that they are feeling how they are acting. Have you ever noticed the dumber the animal, the calmer they are after being shot. You mentioned a woodchuck just plain dying and I have had the same experience with them and opossums, they just die. Hope it helps.

I shot a skunk by my house in the field awhile back and those things are tough. Then after it was all done ,like an idiot I had to walk out to the field and check him out, didn't stink until the wind changed direction on me