We have ducks (remember) and they live in a chicken coop (we'll get chickens in the spring too). Having a mini farm has brought in a mini-infestation of mini rats. But dang, they are smart. I've tried four kinds of trap/bait combinations, so far. They avoid them. I have eschewed poison up till now, but found one that looked like it was completely contained, and wouldn't harm our dog, cat, or ducks. It features a block of poisoned grain inside a u-shaped enclosure that only rats and small vermin could get into. I put this next to an opening under our deck. This morning the enclosure was completely plugged up with dirt; the little buggers just gave me the finger!