I opened our hive yesterday to find about twelve sealed queen cells when last week I couldn't see any contents in the swarm cells (probably needed to look harder!) but luckily the original queen was still there. Quickly started swarm control by moving the brood up to a new box on top of the hive and leaving the queen with old empty drawn comb in the original brood box so hopefully she will think she has already swarmed. (Demaree method of swarm control)
I removed the queen cells to reduce the likelihood of more trouble but these were quite interesting to open up.
This has a developing queen in one cell, a queen larva on a bed of royal jelly an a normal worker larva (collateral damage)
This is a developing queen larva lying in the opened up cell. The cells are remarkably tough to cut with a knife or scissors.
