Mice hate MINT! If you can plant peppermint all around your coop, you should be able to get rid of the mice in the long run. For the short term, get a bottle of peppermint essential oil (costs a few bucks at a natural foods store & some drugstores carry it), mix about 20 drops with a cup of water in a clean spray bottle, and spray around areas where you suspect they may be getting in. And I second that advice from @Ol Grey Mare about figuring how they are getting in in the first place. Best of luck!
thank you so much!! Question - is there any risk to the chickens with peppermint? I am also going to try the bucket trap too. They are making me crazy!