B, A, Up, A
Enter Pig, Boat, Bag, Deer, Bag, Deer as a password.
Get your hunting license at the cabin. Go and press the A button at the deer with a bullet hole in it. You will have to shoot 12 rabbits to obtain the license.
If you were looking for Billy Bob's Huntin' n Fishin' for Game Boy cheats, then you might also want cheats for: