Being surrounded on 3 sides by woods is just an open invitation. Also up until a year or 2 ago we had 4-6 outside cats so there was little to no issues with mice. But the cats declined down to 1 up until a month ago (hit by car, wandered off/or carried off due to predators) then about 2 weeks ago a stray showed up but more than likely was dumped off as it's been trying sneak into the house every time I bring the food out. That one and my current cat have started to tolerate each other finally, as the new one tried to make itself the "dominant" one but I've also had to intervene a few times. I have boxes with old towels/blankets in them covered by old blankets with an old sleeping bag over them on the covered porch for the cats to sleep in at night and a heated water dish.