Lurking but I do want to throw in.. Mice will attempt to fit through even the smallest bar spacing. I had one in a very large, thick plastic container once (long story, no it wasn't his actual home) and he decided to chew a DIME sized hole in the side.. I found him squeezed halfway through. How, I do not know.. He died very shortly after. I assume he literally crushed his internal organs and bones. I had to cut him out which took quite a while, too. Never put a mouse in plastic as a temp spot again. I prefer glass cages with mesh tops because with chewer/squeezers like mice you just never know.. A mesh top is very important if you get them young because they will still popcorn up a lot and can easily jump out of a tank. I've seen one popcorn out of a slick surfaced 1 1/2-2 foot bin before. Had her in it for tank cleaning and she nearly escaped! Once they're older they get lazier, but can still jump. Little ones spend a while hopping though.