I never had problems before. The bag(s) of feed, were just sitting on the patio on a wooden board. Lately I have found small holes eaten thru the bag, and mice droppings inside the bag and around the bag. The solution, I think, I have found is to either put all the feed onto a large plastic or steel bin, or to put the whole bag on top of a 5 gallon bucket that has sloping sides. For the time being I just put it on top of the 5 gallon bucket. So far I have not seen any mice droppings. Apparently, they can not climb a slippery sloping side ?