Drone comb, February

The problem I have about now with the combo-feeder box and ventilator, is that the bees start making comb in it- and I have to remember to get it off by mid February. I am working on a design that mitigates this- but I don't want to get rid of the shared space yet- they seem to really like it there, and I wonder if it isn't a help. Throughout the winter, this is where they cluster, in a mass, and they never seem to make comb at all.

On hive #3, i waited too long- and below is what they made- and in addition, it was full of drone brood, and eggs. Unfortunately, I had to scrape this all off, and am doing so in other hives to and getting rid of the feeding space. This is the only hive with brood in the burr comb though.

This brood also surprisingly showed mites when I cut open a few cells. Its February- its amazing to me that there are mites this early, and two in a cell? where are they all winter? Couldn't I treat in mid-February? Now there is capped brood- much harder to treat. 

Burr comb in the feeder space

Mites in drone cells

Hive #3, in February- lots of bees

My 8 current roof top hives and my ladder access.