A week ago I moved the Queen excluder in Hive D. Yesterday I had a look inside. The Queen appears to be in the lower box now. The sealed brood, including Drone brood has mostly hatched out. Some Drones were milling about above the excluder. Drones are too big to fit through an excluder so they were trapped.
I confidently started taking the frames and shaking them in front of the hive. After about 3 frames I started to worry that maybe the Queen was in the upper box. If I accidentally dumped her in front of the hive she might not be allowed back inside. I stopped shaking frames and decided to return after all of the sealed brood had hatched.
While looking for Drones I noticed a Queen cell in the upper box, above the excluder. This Queen will be trapped when she emerges so I should be able to catch her. Should I release her or move her to another hive? If I release her then Hive D will probably swarm which has advantages and disadvantages. I haven't decided what to do. My inclination is to release her into the lower box and allow the colony to deal with it.