>>I don't provide an upper entrance, but I've been considering it...drilling a hole near the top of the box.

Is it because you've seen condensation and would like to bring the moisture out?

>>I winter my nucs on top of production colonies...

Do you place 2 nucs, side by side, over a full size colony?  (One could cover both nucs with a single [oversized] cover.)

>>I do top insulate with foam...directly on the nuc's inner cover(which is a grain bag)...

Do you use a grain bag to absorb moisture?  Doesn't a grain bag sit directly on the top bars preventing bees from crossing over the frame tops?

Waldemar

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