Very cold winter for us this year. One January night I went out and put an ear to the hives. I can normally hear them buzzing. I heard nothing. The next day I listened with a stethoscope, again nothing. I carried my two dead and very light hives into the garage for safekeeping and to prevent mold. The next day I opened them up and found they were actually alive but essentially out of honey. I immediately made some candy board and placed it where the feeder can would go. For the rest of the winter I checked the candy every few days and added more when it was gone. On a few warmer days I had a few bees flying around the garage but no big deal. I concluded they need to see light from the doorway to come out and the garage was always dark. I also noticed that the inside of the top cover tended to be dripping wet from condensation. I previously kept a piece of Styrofoam on top over the winter assuming it would prevent this. Sure enough, I put the Styrofoam back on top and the condensation was all but eliminated. I lucked out and saved my hives and the cost of more bees this year. I'll bring them in every year from now on.