Mice can have babies every 21 days.
A mouse is mature within 1 week & is then able to breed.
If unattended they quickly become exponential in numbers.
Mice will look for comfortable warm areas to build nests, the insulation inside walls, in the attic, in closets and even inside your new mattress or sofa!
Mice carry disease, they urinate & defecate from 70 to 140 times per day, depending on the amount of food available.
That’s a lot of poop!
That is only one mouse!