I also don't belive in killing something just for the fun of killing something. There's got to be a reason: I'm going to eat it; I'll use the hide for something (e.g. coyote/fox); or it's a non-native species that shouldn't be there (e.g. feral hog).
Before you shoot a chipmunk for the fun of it, you better check your state's game regs. Here's what PA says.
All wildlife in Pennsylvania is protected by the Game and Wildlife Code and is classified as follows:
Game Animals: Black bear, cottontail rabbit, elk, squirrels (red, gray, black and fox), snowshoe hare, white-tailed deer and woodchuck (groundhog).
Game Birds: Brant, bobwhite quail, coot, gallinule, geese, grouse, Hungarian partridge, merganser, mourning dove, pheasant, rail, snipe, swan, wild
ducks, wild turkey and woodcock.
Big Game: Bear, elk, white-tailed deer and wild turkey.
Small Game: Game birds and game animals not classified as big game.
Furbearers: Badger, beaver, bobcat, coyote, fisher, mink, muskrat, opossum, otter, pine martin, raccoon, red and gray fox, skunk and weasel.
Protected Mammals: Wild mammals not classified furbearers or game animals (For example: porcupines and chipmunks are protected).
Protected Birds: Wild birds not classified game birds.