How did you critter proof it, DD? It seems like the mice out here can get into anything.
We have mice outside, but we also have ants, 'possums, raccoons, blackbirds of all kinds, all of which I have caught in my garage if I leave dry goods sit on a shelf for too long with the door open.
As far as the ants and mice, I built it out of "Melamine" board which is particle board with a thin plastic "formica" layer on each side. I also used some scrap unbent guttering roll of flat sheet metal, about sixteen inches up all the way around the bottom. I glued every seam and screwed it all together, Kind of hard to chew through and anywhere they try there will be evidence.
The ants also get a type of window sealing weatherstrip to contend with.
The doors close onto a rubber gasket. Getting all that worked out and a great double fence latch adjusted to keep it all tight will foil the birds, raccoons and hopefully all the chipmunks as well.