I checked up on some hives three weeks ago. They were quite full of honey, I didn't have any spare boxs on me and I noticed they were low on space. One hive had two supers, one deep and one medium.
Anyway, just this weekend I went back to these hives, to do a honey extraction and provide another super. Unfortunately, the hive had been abanboned, it was full of wax moth which had done a suprising amount of damage during this time.
I can't recall if I checked the brood chamber for queen activity. It's shocking to me that I had a good strong healthy hive, then not even a few weeks later the hive swarmed. Could me visiting the hive, opening it up trigger them to swarm? Maybe they were already planning on doing so because the queen didn't have enough space for eggs?