Or just live really close to farm fields. We're across the street from one #midwestrurallife. We're not slobs but that doesn't matter, because as soon as the combines start harvesting, the mice start arriving. Only way to stop it is to go around the entire outside of your house and seal off any openings that are larger than a pencil, because surprise, mice are liquid and can squeeze through some pretty small ass holes. For a while they were coming though the dryer vent output.