Thanks for the further description of your operation. So the queens are clipped pre- introduction to production units - that makes more sense than the scenario I had imagined. I had read of British commercial guys (not operating near the scale you are) going through every colony in the spring and clipping. It would be ideal to supply a new (clipped) queen at the beginning of the season as you do; the presence of a new queen is known to be a big hedge against any swarming anyway. Small beekeepers like me tend to let a queen go on for a couple of years or more, and they are sure to want to swarm that way! It must be nice when you can find the queen on the first try -- BTW, if the colony is exceptional do you ever save the older queen for possible breeding, or let her continue in production colony, or is she destroyed anyway due to age? Thanks, JWG