Anything that poisons the rat will poison anything else that eats the carcass. You want to dispose of dead rats as soon as you find them. They don't seem to get very far. The one I baited (it thought my converted garage was a place to forage) was found just a couple of feet from the house.
Unfortunately, raptors can be poisoned from dead poisoned vermin, so be careful. There are other ways to get rid of rats.
