I voted for stun, but after reading all the comments, i think PK would be a more appropriate response for me.
I don't try to "stun" the rat, i leave it in the brown paper bag that it comes in (they come double bagged), and i walk outside and slam it against a wall or pillar, stairs, anything....then i walk 15 feet or so and pick up the rat that usually breaks through the bags and goes flying.
when i hit them hard enough to break the bag, they're always completely gone....dead still. If i don't get a good hit and the bag doesn't break, there's been a couple times where their legs are still twitching slightly, but they're obviously not going to "come back" and put up a fight against anything.
Just wanted to clear that up!
Thanks