i have two female pekins and we have found dead mice in their coop they love killing mice. Ducks are good mouseres because mice dont try to run away they just sit there and then with on sharp peck the ducks crush it internally. it's gross but they're helpful
I learned recently that in homestead times, settlers would grow pennyroyal and spread it on the floor in the kitchen and feed areas to keep away mice. The lady I spoke with is a professional re-enacter who maintains a historical site by actually living there part-time, and she swears by this. I haven't tried it yet, but I'm planning to grow some next year to try out on my feed room floor.
Pennyroyal keeps out fleas, anyway. I once lived in a city apartment built in the old attic/servants quarters, with wide gaps between the old pine floorboards. These quickly filled with cat hair, and then fleas. The only thing that solved the problem (we tried various bug bombs from the hardware store) was strewing the floorboards with pennyroyal. Got the idea out of, if I remember correctly, an 18th-century book on housekeeping, which said pennyroyal was "proof against flease, rodents, and other pestes."