The purpose of rotating brood boxes is to reduce the chance of swarming. Because it is quick and easy, it is a favorite maneuver of commercial beekeepers or those with many colonies to handle. In that case, it is probably somewhat effective at reducing the swarm impulse, at least for a while. If you find your winter cluster is very small and easily fits in one box, you may want to remove the empty box until the hive regains strength and numbers. In the meantime, you have an opportunity to maintain that box, re-paint it, clean frames, replace frames, or do whatever needs to be done.
