We made the switch to live traps and let me tell you, WAY MORE AFFECTIVE! Not only could we catch 4 mice in each trap, but in about three days, we'd caught all the mice. No signs of them for the last 4 days now. We had kill traps set up still, but the mice didn't go near them. Hurray for not killing the mice AND having it be the most successful form of pest removal!
P.S. Released the mice out of the live trap at a park a small distance from the house. Backyard release = mouse back in house.