I picked up 6, 4 frame nucs that day. They were in split 10 frame boxes all off the same rails at an isolated yard around the end of May. I think that was the mating boxes but I dont know if the bees they were made up from came from different sources. I remember the seller commenting that the one nuc was a bit light but should catch up. It is pure guess work that that nuc got made up with a load of lousy bees. I think the queen was laying well.
I should have spotted something was wrong sooner. Simply lack of experience. Apisbees, I think, had a post on the normal ratio of eggs to open brood and open brood to capped brood and again from capped brood to frames of bees. Kind of a rule of thumb but based on the pure math of number of days in each stage. If one of the stages is not going on schedule it should show quickly if you know how to appraise it.
The conscensus seemed to be that nucs dont have mite problems in the first year so it must be faulty queen problem. Once the mites were taken down though, population took off and the brood pattern went solid.
I think I have read that over sensitive VSH bees have been produced that uncap too much brood and wont build stores. That probably was instrumental insemination but it points to what a delicate balance there can be to getting sustainably treatment free bees. What method do they use to become treatment free? Some avenues seem to be by way of reducing the fertility rate of the mite resulting in fewer offspring per cycle. Some methods seem to rely on heavy grooming; others on shortened emergence periods by the bees. Maybe some are a combination of the various methods.
I sure would like to see a means of assessing what the actual causal mechanics are where bees appear able to go on year after year without treatments. Are some successful for totally different physical reasons than others? It would save a person a lot of blind stabs if that were conclusively known, wouldn't it?