I also put mouse guards on two of the hives. These are metal gates that fit across the front of the hive that, as you guessed, keep out mice. Mice LOVE to overwinter in a hive where it is nice a warm and they can make a nest with the wooden frames and wax.
I have another guard on the way from one of my favorite bee equipment companies, Brushy Mountain.
So while my kids remain potty trained and we had no behavior problems at our big harvest dinner, I was so happy for our milestone: how joyous my daughter was to see the bees close up.