I don't know about the rules for Oregon, but I'm pretty sure this isn't Ok, and probably unlawful. As a landlord, it's their responsibility to deal with the problems of the apartments they rent out, which includes infestations, if they don't, they can be fined. He needs to do a lot more than hire a handy man to spray some insulation, that's not solving the problem, it's hoping it goes away on it's own. Meanwhile the mouse just creates more destruction and uncleanliness. He needs to make arrangements for an exterminator and probably a cleaner to clean all the droppings. I'd look into the renter rights for your state because if your landlord refuses to fix this problem, there are actions you can take. Ones I know of are, you can hire an exterminator yourself and deduct it from your rent, withhold rent altogether until he fixes it, and contact the city and report him for not upholding his landlord responsibilities.