I hear all sorts of examples of ways to kill the mice, but please remember that there is more to be done, or else you are just leaving the mouse hotel empty for the next guests.
I'm not sure that someone can completely get rid of mice forever, but there are certainly things to do to try to reduce the issues. Mice are generally looking for food and warmth. If you make it harder to get those things, they will not be as happy to stay in your house/garage/
chicken coop.
Remove food sources. Only
feed pets what they can eat during the day. And remove anything else at night. Make sure you sweep and clean the kitchen and anywhere you eat regularly. It might look clean enough, but it doesn't take much to make a meal for mice. For food storage, make sure packages are sealed tightly, preferably in smell proof and chew proof containers.
Clean up around holes and trails as much as possible. Most rodents will follow the smell and pheromones of previous rodents. You could kill all the mice in your house, but if a new mouse happens by and smells the previous mice, it will follow the trail to whatever food or nest the previous mice liked. This needs to be done inside and outside. There are some enzyme based pet sprays for cleaning up
urine smells... those would probably work, but at least use
soap and water. Not to mention all the diseases they leave around.
Plug up holes. This is much harder, but you need to check in and around cabinets, behind furniture, go around the outside of your house and look for cracks and chewed holes where they can get in. If your house is on posts with a crawl space... good luck. If you have a full foundation or basement, I think it's a little easier... but they are small and can fit in very small holes.
Clean up and remove clutter. Again, this needs to be inside and outside. Those stacks of clothes,
books, magazines, half finished projects,
boots, coats, etc needs to be all cleaned up and put high up out of the way of the floor. They make the mice feel safer while exploring and are more likely to expand their family or cause more destruction. Outside, thin or cut back bushes close to your house. Rake away the leaves and debris. Cut the grass short. The more exposed they feel, the less likely they are to stay in that spot and the less time to find any food or ways into your house.