When we moved into our "dream house in the country" it was infested with mice. In the evening watching tv I would see mice running behind the tv and around the perimeter of the room. We did not want to poison the mice in the house because of the odor, so we tried spring traps, glue traps, electronic traps, frequency generators, and even a cat. The population did not grow but it did not decrease either. We tried to patch all holes or any entry point we could find, but we were still loosing the battle. Then attending a Home and Garden Show one of the presenters had poison bait stations that you put outside your home so when the rodent goes to a better place he is outside and there is no odor in the house. I said how much and was quoted several hundred dollars for enough stations do my house. Not in the budget.
Shortly after we were finishing a shed and I found several pieces of PVC pipe/conduit scrape and thought they could make bait stations that would protect the poison from our pets and children and still allow the rodents to feast to their hearts content. I made a dozen stations. At first I checked the "food" supply weekly and replaced as needed, after the first winter I reduced checking to monthly, now many years later I check the stations in the fall, Thanksgiving, New Years, and the first of spring and replace the bait as needed. Now I have only seen 3 mice in the house in the last 5 years and was able to catch all with good old spring traps.
Find a piece PVC pipe 1-1/2 inch diameter to 2-1/2 inch diameter. (small enough that your pets cannot get to the bait) 12 inch to 24 inch in length (mine are 16 inches)
Drill a hole in the middle of the pipe I used a 1/4 inch bit because it already was in the drill.
Thread a piece of mechanics wire through the drilled hole and out the end. (any wire or cordage could be used as long as it is flexible enough to go through the hole and out the end) The length of the wire is twice the length of the pipe, (mine is 32 inches)
Purchase rodent poison that is formed into stick, bar, or cube with a hole in the center all the major brands make a product like this. (I use Just One Bite Brand, but it getting hard to find in the store D-con and Tomcat both make a cubed product)
Run the wire through the center and bend the wire in a hook so the diner cannot grab and go he has to eat in and leave some for the next patron.
Pull the wire from the drilled hole and the poison will slide into the pipe and be secured from the elements. Wrap the excess wire around the pipe.
Place the loaded pipe outside around the foundation of your home or building. I place one close to a corner and then the middle of the wall. Also place close to the garage door and back door. Suggested spacing is a bait station approximately every 25 feet. Check the "food" supply weekly at first and as you get a feel of your success rate the frequency can be lengthened. Also if raccoons decide to invade the bait stations, just put a rock or brick on top to keep them from stealing the bait and station. These stations have been very effective on mice, rats, chipmunks, and voles.