I know an old farmer who just, when he wants chicken for dinner, goes outside and pops the first one that walks by with a 22. That sounds very low stress to me provided your aim is good. My dad uses a hatchet. I have yet to do the deed myself, but I'm thinking the 22 method sounds like one that I'd be more comfortable with personally as it's much less up close and personal. However, I've heard that it's harder to get the blood drained from the bird properly if you shoot it, so that may be something to take into account as well.