More information is needed. How long has the colony been in the hive? How large is the colony? Do they appear to be quietly organized as a colony? Do they sound queenless? It is quite likely that a swarm moved into the equipment. The queen may be a virgin and so small that you didn't see her. In a week or so she may get mated and start laying. It is unlikely that bees moved into the hive without a queen, but it is not impossible. James C. Bach Yakima WA [log in to unmask] [log in to unmask]