I have had some colonies do the same. They were all Q right but no eggs or brood and rammed full of stores. I suspected this from about November but never opened them up. 1 just dwindelled away to nothing and died. 2 others ended up with a cup full of bees which a frost would have killed. Another 2 had a drone laying Q and a Qless which never had laying workers but obviously no Q. So despite the temps a few weeks ago my only choice was to go in and figure all this out. I decided to cage the 2 Q's despite them having no evidence of brood at any stage and put them in the other 2 colonies having removed the drone layer. Check back a few days ago and they have 6 or 7 frames each of brood and look fantastic. No idea what was going on or why they had stopped laying in their original colonies. It wasn't a Q problem and had loads of pollen and honey stored. Maybe this Labour government is to blame and the workers went on strike. Could be a moral in this story 
