always dead bees inside my
mating nucs-and at times earwigs-small hole entrance-one bee at a time-needs to
be close or at floor level-so bees can clean out dead bees-another point that comes to mind is that- it is better NOT to have any bee space between the top of frames and the lid-reason being is the bur comb that will connect the frames to the lid-
when I start mine out I have something of the same problem but once fully populated the problem vanishes. I should tell you that I have my baby nucs with a bottom entrance and a robber screen so the undertaker bees still has to drag the dead up some distance to toss them out the front door. I would also highly advise ron than robber screens are essential anywhere you have significant bee population.
I do allow for bee space between the top bars and lid. the really populated baby nucs (typically the queen was not caught on schedule) will still burr comb the space. here if this space is too small it become a likely home for the shb in large numbers.
drivert as a feed was first brought to the bee keeping folks attention by Steve Taber perhaps 30 years ago. He used it in great quantities in rearing queens. It was a bit more expensive than suger or hfcs but was considered to be superior feed since it was inverted.
I did measure my top bars of my baby nuc frames yesterday and yes they are 9 and 1/4 inch. this allows about a quarter to three eighths of an inch between the two set of frames (20 total) in a standard illinois depth super. I use a cross bar in the middle of the super that is about 1 inch wide. like rdy I place a single box of baby nuc frames with foundation over very robust hives for growing out. I also have one or two hives here during the most active queen rearing season that are top to bottom baby nuc frames which allow me some resource to tap to boost existing baby nucs or to make up baby nuc boxes in numbers if I have a large number of cells that make. these are also real handy when the weather turns just as queen cells must come off.
since I use straight foundation in the baby nuc frames they also produce some very nice looking comb honey for the chunk honey I sell.