So one of my hives does not respond to the winter "knock" test; no buzz at all. Because of this, when it was colder in Dec. I thought it had died. But much to my surprise last weekend when I opened the top there were bees. There are not a ton of bees, maybe only a few thousand. There is a laying queen and plenty of food stores, these bees are just super-calm and quiet. They hardly do anything unless I start taking out frames where the brood are, only then do a few of them start buzzing and getting aggressive. One other behavior of note, I don't see them doing much to any orientation flights during the day, unlike the hive right beside it. I don't see any indication of sickness or disease, just some SHB, but that's pretty common in all my hives. These bees are small too, look like the hive is mostly nurse bees with a handful of foragers. I'm really not sure what's going on or if I should be concerned.

Anyone have an experience like this?