Hive E is having a Varroa mite crisis. I checked today and for the previous 2 weeks. Each time I found hundreds of dead Varroa mites.
High mite drop can be a factor in colony collapse. I don't expect them to perform well next season - if they survive through the winter. I expect them to be weakened, and any brood raised in early spring will be heavily infected with Deformed Wing Virus or other diseases symptomatic of Varroosis.
I had hoped that the colony would be better able to manage Varroa. They've been untreated for a significant period of time. The swarm came last season from a feral hive in Barton.
Earlier this season they were very bad tempered which may be related. I should have checked whether they were Queen-Right (you bang the side of the hive. If the roar calms down quickly then they have a Queen. If not then they may be in distress and Queen-less).
I doubt whether replacing their Queen this year would have led to this situation. Even if she had no mite tolerance there would have been a time lag to produce vulnerable brood, and then a further lag to build up mite numbers. It seems more likely that this is the difference between mite resistant and mite tolerant. In the former there are hygenic behaviours or adaptations which inhibit Varroa mite reproduction. In the latter the bees just tough it out. I suspect that Hive E is only tolerant. We'll see whether it is tolerant enough.