...not trying to demonstrate my inexperience ..just wanting to understand clearly...
Rather than introduce acquired queens you then allow the nucs to raise their own replacement Queen?
Have you always done the same, and are their are many sources locally for unrelated drones to fertilize the new Queens? (wondering about the gene pool)
I like the way my bees came through the winter with very few mites (i opened up lots of drone cells and found very few, most had none, and their populations are explosive)and SHB's (no treatments) so I want their genetics. As far as drones are concerned, I have at least 3 other bee yards near me that my queens will mate with. Drones stay close to their home apiary usually less than a km. queens fly farther to get away from related drones. You can tell a queen that has mated with it's own drones, the brood pattern is real spotty. Briefly, the male has 2 sets of genes. One is a direct match of the queens and one is from his grand father, he has no father. If the egg is from his grandfather, it is viable, if the genes are from his mother, it is not and the bees will remove them. Hope this helps.