hello so I am in my first year beekeeping. started with 5 hives going into winter. got into the 40s today so I was checking on my hives and found that my 1 two story nuc was dead from moisture (due to my faulty installation of quilt box). Also 1 of my 4 full size hives was also dead. Due to my stupidity and inexperience I didn't get mouse guards on the hive entrances before my entrance reducers got frozen on and I didn't think it was a big deal. well a mouse had taken residence in my fullsize hive and had made a mess of things and definitely contributed to it dying out but when checking the dead bees 30% had mites visible on them. they were definitely struggling from that as well even though I had treated them with maqs.
Now my questions are how much damage can mice do to the remaining hives? Will they usually kill hives that they infest or just make a mess of things? What are my options for my 3 remaining hives? should I simply put on mice guards but what if they already have mice in them? Has anyone ever used mice poison in their hives? if so do you know if it will hurt the bees? Could really use some advice i'm going to be worrying about my 3 remaining hives all winter cause of this mouse getting into my other hive. Also trust me never again will my hives go into winter without mouse guards on all entrances!!! thank you ahead of time for any help