Last year I started a new hive in a beemax hive. I mixed 1/2 pierco with 1/2 wood/foundation to see how they took to the plastic frames (I alternated 1/1)

They didn't seem to mind the plastic, but only drew out 1/2 the box. I added another box, and they proceeded to draw that out - but again, only 5 or so frames - all to one side - not the middle 5. They were a decent hive aside from that - lots of bees, but I never got them past the 1/2 hive.

I assumed I'd lose them over the winter (I'm in Massachusetts), but they were fine - they had 5+ frames of stored honey, and made it through the mild winter in good fashion.

2 weeks ago, I opened the hive to find no eggs/brood/etc. But, I had one open queen cup, so I decided to give them some time to check and see if she mated, and is laying. I went back in yesterday, ready to add a frame of eggs/brood from another hive, but there was one frame - both sides almost completely full of capped brood. Some larva in spots, but almost all capped brood. No pollen, no honey/nectar - just a full frame of brood - from top to bottom and side to side.

What is up with these bees? While I'm only a 4th year beek, I've never seen an entire frame full of brood - it's always had the typical brood/honey/pollen look to it.

Is this hive on something? Is this semi-normal? My good hive has been doing great, and this hive seems to be two or three grade-levels below them in terms of bee-competence.

Any thoughts would be appreciated.