Laurie - The broodless colonies, where they backfilling the brood nest with honey? If so they may be getting ready for a swarm. It is said that about two weeks prior to a swarm the bees put the queen on a diet and she doesn't lay much at all. Did you find any swarm cells or otherwise queen cells during the inspections?
Another thought is, The bees .. What breed are they? Russian and russian hybrids will shut down brood rearing if they find that they are not able to get nectar/pollen in ample supply.. Just a thought..
Another thought is, The bees .. What breed are they? Russian and russian hybrids will shut down brood rearing if they find that they are not able to get nectar/pollen in ample supply.. Just a thought..