Queen Cells - checking top Brood Box ONLY

[B+.]

When it is time to main flow, I unite hives so, that productive hive has about 6 langstroth boxes. For example if I have 3 hives with 4 boxes, I make from them 2 six box hives.
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Thank you Finman. This explains a lot. This is the way that Michael Palmer works in his queen rearing too. Supplementing the colony with emerging brood makes the colony very strong. If, as you have done, they are foragers. you make a huge colony with a massive foraging force.
I think the problem a lot of us over here have had is that your claims seemed unrealistic from a single colony. Now that we understand how you do it, I hope people will be more tolerant.
Am I right in assuming that you unite the colonies with newspaper between boxes? If not, how do you do it?
Incidentally, what is your main nectar flow? For us, OSR flowers in April and many of us would have problems building our colonies to the stage where they could donate frames to strengthen other colonies. If it is later, and you have had more time to build up your colonies, I can understand how you manage to do what you do.