[minz]

My earlier graft I had about 10/16 drawn out with a lot of burr comb, Zero hatch. I never had a zero before. I was really struggling to find the cells for all the wax. I messed with the cells way too much I think. Can tipping the frame and cells too much cause them to die? I put a knife in hot water and cut the cells apart in a quick swipe (frame upside down). Put them in a Styrofoam cooler with a bag of hot water with bubble wrap over the top while I made up my queenless nucs. The queens seemed fully developed in the cells.
My second set of queen cells I got about 16/20 and since my grafts were about a week apart I checked on hatch rate while I was over there. I can not figure out what I did different than the previous years except for the burr comb issue.
I did find the UoG’s Utube on the queen cell transporter and they did about the same transport as me except with cedar rather than bubble wrap.
I live in the wet side of Oregon and our April was dry (drought) and warm. Our spring came 3 weeks early.

 

[crofter]

I have seen hot water bottle and styrofoam cooler instructions that made me wince with the feeling that temperatures could overshoot for a while. I dont know how many degrees and for what time duration it would take to knacker a queen in a cell so my hunch is not worth much.

I think shaking damage is supposed to damage antennae and wings, not kill them.

 

[little_john]

The burr comb around 'the bad batch' - did it cover the tips of the q/cells ?
LJ

 

[minz]

The burr comb around 'the bad batch' - did it cover the tips of the q/cells ?
LJ

Some did yes.
I was real gentle with this second batch. After Franks comment i am hoping I do not end up with 20 queen less mating nucs and no new cells for them. I took a grafting break when I thought I had 26 new queens and nucs and the local flow starting with bloom swell (blackberry).I may have to grab a couple of weak hives and make up a quick cell builder if things are bad.
I normally would just put them into a cooler and let them roll around. I guess it was working too well?

 

[little_john]

Well, I'll tell you what I was thinking ...

As you know, under natural conditions queen cells are attached to combs - either hanging below them, or positioned on them within the inter-comb space. But queen-cells drawn on a cell-raising bar are effectively hanging down within a substantial void - hence the drawing of wild comb attached to those cells. Indeed, I'm surprised we don't see this happen a lot more often. Anyway, the point I'm making is that this is an unnatural situation for the bees to find themselves in.

The tip of a queen cell is porous, as too are all cappings of cells containing brood, in order that the insects within those cells can breathe air prior to their emergence. Now if a queen-cell tip is covered with non-porous wax, as could well be the case with wild comb, then the queen inside that cell will suffocate. Under natural conditions, wild comb would never be drawn attached to queen cells, so this particular problem would never arise.

I'm not saying that this is definitely the cause of the deaths in your case, but I'd say it's a definite possibility if the queen-cell tips were fully covered.
LJ