Lots of my stored crops are being eaten by mice, how can I control this?

Use either traps and bait (or both).

Chocolate is a very good way to attract mice to a conventional trap and much more effective than cheese.

Put one or two traps close to the stored crops and inspect daily.

alternatively; place purpose made plastic bait boxes containing an effective rodenticide near your stored crops.

These are designed to protect the bait from larger animals or pets.