While doing a inspection, I found this queen cell on the edge of one of my TBH combs. The hive is a package installed this year, and is still building up. They have plenty of space, so I wouldn't think they are thinking of swarming. Maybe a superseding their queen? This is the only one I saw, and as far as I can tell its empty. If they are thinking of superseding, do they normally build multiple queen cells?