I finally opended one of my two hives today and confirmed what I've suspected for a couple of months - the colony died sometime in mid-winter. All I've done so far is pull out the two outermost frames from the top box, which were both filled with capped honey. I can see many dead bees clustered in the center with a few scattered around the periphery. I can also see that there are several more frames of capped honey. These bees went into the winter in good numbers and with plenty of stores, at least in the honey department. I not positive about pollen. The only thing I did to the hive bodies to prepare for a northern Michgan winter was to wrap the exterior with 1" blue foam being careful not to block the entrance or the upper vent holes. My question is what should I look for as I fully tear apart the hive later that might give me a clue as to the cause of this calamity? And could it have had anything to do with the foam wrap? Thanks for your thoughts.