I would say cast swarms, swarms with virgin queens. You have a crowded hive with a plugged up brood nest because of the intense dandelion flow and the bees decided to start swarm preparations. Now you split the hive and make nucs, but if the nucs are assembled so they are packed with bees, with the frames full of brood, honey, and pollen. You haven't addressed the problem that caused the bees to start the swarming process. So the bees will protect the other cells in the nuc from the first queen that emerges and they will swarm from the nuc with a virgin queen.
I do not agree with some of the advice given above. The queen in the hive that is being forced to swarm because the bees as a general population find it to crowded, lack of queen pheromone, bad weather or poor flow and to many idol bees with nothing to do in the hive, or any other reason, is the population producer in the hive. To keep the bee population in the bee yard increasing the queen that is pulled to stop the hive from swarming should be given all the resources so that she can continue to lay at her maximum rate. I leave her with 6 or 7 frames of brood and bees to cover 9 or 10 frames, and place a empty brood super on top. This will give her space to lay, bees to support her full laying potential. In 4 to 5 weeks this hive will be back at full strength and ready for the main honey flow.
Sorry Iddee but I cull swarm cells. If I graft and raise cells I only place one cell in each nuc or hive that I want a queen raised in. Before I place the cells in the hive I will reject any cells that are smaller than the others, as this could be an indication that the cell was not feed as well as the other cells. In the hive the bees start to build cells over a number of days so a caped cell could be anywhere from 9 days (just capped) to 16 days (ready to emerge) old, that is one week. The cells are drawn out and capped with new wax which is white, as the cells age they get darker in color, and just before they are about to emerge the bees remove some of the wax from the tip of the cell so it is easier for the queen to release herself. With this knowledge in mind when I come across swarm cells I will cull all that are not capped as they are over 7 days away from emerging. The building of cells to this stage will not have effected the queen or caused her to slow down her laying yet. Next I will cull any cells that are short or small, small cell could be stunted queen. Next I will look for indication of the age of the cells, darker = older so I will cull light ones before the darker cells. I also consider location of the cell on the frame, when I add a cell to a nuc we place it up between the top bars where the bees are clustering. If the cells are along the bottom of the frame you need to make sure there are ample bees to care for the cells and keep them incubated. And for the most part I only place 1 cell in any nuc or leave 1 cell in any hive. I try to insure that it is a good mature cell, hasn't been shaken or bumped turned up side down. And placed in the nuc so the bees are assured to continue to keep it warm and care for it.
