Just thought I'd share my story. I know it's not uncommon, but is rare to catch. Now, all the pro queen breeders may see it all the time, but I just got lucky. I was looking through a hive yesterday that I had gained through a removal about two weeks ago. I guess I injured the queen, and so they raised more. I was unaware of this until yesterday. So I open the hive, and a start finding all these hatched queen cells. This upset me, as I had just finished build a queen castle on the night before, and my goal was that I wanted to check the bees the day before as well, but didn't get around to it.
Anyway, as I'm looking through, I spot one queen cell not hatched, but also not yet destroyed. So I'm starring at it, when I spot out of the corner of my eye, TWO queens running up the frame, but not fighting each other (yet). I frantically grab a queen cage that luckily was sitting there from the cutout, and caught one. But then when I ran to get another queen cage, I lost track of the other loose queen.
I grabbed the queen castle and ran back to the bee yard. I place the caged queen in one chamber with what I believe was queen free frame of bees. Then I placed the frame with the capped cell in another chamber. I checked the frame a half dozen times for the other loose queen but could not find her again. The last frame I left in the original box. If all goes well, I may end up with three nucs from one. If all goes poorly, then I suppose I'll end up with only one, which is what I started with. I suppose if things really fail I could lose the whole batch, but since they were feral to begin with, and I got paid for the removal, then the heartbreak would not be too bad.
Anyway, just thought I'd share my fun experience. Never again will I go to the bee yard without a handful of queen cages, just in case.