There could be many reasons... But this is the main reason we don't buy hives in the fall or winter, you have no idea what preceeded the winter. We have no idea what actions were taken to medicate the hive, what precautions were taken, did they have tracheal mites or varroa mites? At least when we purchase a hive in the summer we know what the condition of the colony is in when they cluster.
I was a little concerned when I read your first few posts and realized that you had acquired this hive in the middle of winter. Winter is when the bees are clustered up to keep warm, you should never inspect them when the temps. are below 45 degrees, it takes away from their heat they have generated in their cluster. If the queen gets chilled, she may never lay again, and the colony numbers will dwindle, the colony won't even be able to supercede her because she can't lay a fertilized egg. The more stable the internal temps. are the better off the colony will be throughout the winter.
Look at it this way... At least you have plenty of drawn comb to start another colony, and you will know what state or condition they are in when winter sets in next year.