Just make sure you put their food and hay in a container that a mouse can’t get into and you should be fine. Unless a mouse has a disease it can’t really hurt your buns and the actual chance of the disease they carry being in a mouse is pretty low in most areas. We had FOURTEEN mice last year in our house because the board covering the crawl space warped and came away enough to let them inside.
Now, from experience, I bought every humane trap on the market and they all suck. The little green house trap works the best at catching them, but they can take their paws and pull the door open. I caught three before one figured it out, he took his two front paws and dug furiously at the door until he caught the edge enough it pulled open and he ran right out. While my boyfriend was holding it! After that, all the mice knew the trick and not a one would stay in the house and it became a food station for them.
What I did was I made my own. I took a plastic lid like to tupperware, or one of those spring mixes they have in the store (long enough to hang over the edge of something) and counter balanced it with a DVD. I put a lafebers seed ball (they LOVED those things, would go anywhere for them) onto some peanut butter (just a small dab to hold the ball in place, not too much as the mice can get it stuck in their throats) on the end hanging over the counter and made sure it was over far enough that the weight of the mouse would tip it but not too far that it would fall before the mouse got to the end. Underneath that, I put my 13 gallon trash can. Mouse went for seed ball, lid fell down into can, mouse couldn’t get out. Make sure it’s at LEAST 13 gallons and tall though, if it’s ANY smaller the mouse can just jump right out. The 13 gallon one was just barely tall enough, the mice could jump nearly to the top as it was.
I caught 14 mice that way in about a week, after over a month of trying every humane trap on the market. I could’ve saved myself a lot of money. 