Use an incubator like many do for queen cells.It is for a customer who wants 1-5 day old bees for proprietary research. Nuc won't do because the bees would be mixed. They do not want foragers. Thought of putting brood above an excluder, but those bees which would go to cover the brood would be about 1-14 days old. How long does the capped brood need to stay warm?
They want a supply of these newly emerged bees weekly over a period of several months.