Several years ago I boarded my horse with a friend from New York who had a novel approach to the little critters. He didn't want to leave anything around that was poisioness or would let the mice go somewhere to die and start to smell. So he would put out flour and cornmeal mixed with quick dry cement and a dish of water next to it. The mice ate the cement mix and then got a nice drink of water. The end result was they would die because their little tummies became concrete and they would die and not smell. Funny thing is it worked as you would occassionaly find the dead rock hard body lying somewhere.