The most natural method is ... CATS...
I have several out side mouse getters, they often go hunting in the surrounding fields because they have removed all from the immediate area ...
If you know someone with indoor cat, you can spread the litter box contents around the perimeter of your out buildings ... it is a great deterrent for pests of all kinds. They will not make a home in a building that they think cats are around... Plus it's a good fertilizer for the grass and plants... :smile:KennyV