If you think about it, any kind of feral animal living inside your home would be bad. How much concern would it bring if feral dogs frequented your property, or if feral cats found shelter under your home on a regular basis? Our guess is that it would concern you greatly. Now, what if the feral creatures were much smaller? What if a mouse and its friends came to live in your home, staying out of sight during the day and coming out at night?