There's a honey flow on. All the hives in my out-apiary have stores now and there's a lot of activity. The bees are noticeably better tempered.
The roaring that I heard recently was probably the bees fanning, to cool the hive and evaporate excess water from the honey. I knocked on the side of A Hive this morning (the one which roared); they revved for a moment and then calmed down. Not queenless, just busy.
C and D Hives both have brood. I had a better look at C because it was easier to handle. Brood in various states on at least 10 sides of comb. These are Commercial depth frames but not completely covered in comb.
I'd put a deep super (ie a standard brood box) on C hive which the queen has evidently moved into. This is not great management. I saw patches of a few dozen larvae, honey-bound by stores. I'm sure that they'll work it out.
The worrying news is that B Hive is queenless. Their supersedure appears to have failed. They have stores which surround empty cells. I suppose that they'll get robbed by and then drift into either of the more successful hives.