One of my hives was super vigorous in February too, but then later died. On inspection last weekend I found that there was a ton of brood all over, and the bees were spread out all over the combs apparently trying to keep them warm. When the weather got super cold again the very next week (stupid weather!) that was the end. I used to think that hive was super awesome for being so ambitious, but apparently the tortoise may have won again, the rabbit started too early.I lost my last hive just before Spring. I had seen what looked to be promising activity in mid February but on review of the video I took I'm now convinced it was robbing. When I got into the hive in late March there was quite a bit capped honey in the upper deep but only a handful of dead bees. I blame the failure on my neglect but the 22 lbs of delicious honey I extracted will remind me to do better with the next attempt.