Kathy: I have seen the perfect bait station for any substance that you want to use for rodent control. Take a "T" made of PVC pipe narrow (2") enough to only allow the targeted species to enter. Wire the "T" to a stake driven into the ground upside down with horizontal arm on the ground. Place the bait at the intersection of the two arms . The rodent will enter and feed on the bait. I read that zinc phosphide has been used. You can put a threaded cap on the vertical arm so you can reload the station. Arnold > >