I agree with Patrice, Henry. I have had mice come into a couple of places where I have lived...and it was not because of unclean conditions, it was getting cold and they managed to find a way in. We even had an issue in one place with rats in the garage...but we did live out in the country and they found it to be a nice warm place to nest.
I am so sorry that you have lost so much of your stash... :( :( :(