In the early 80's Dr Orley Taylor, Kansas, did an experiment to study queen mating. Using transmitters and radar he followed queens and drones on mating flights in Kansas. As I remember , his conclusion was that queens fly at least 3,000meters from their hive before they mate. Drones never venture more than 1500 meters from their hive. This keeps a brother drone and sister virgin from mating. I was at a research lunchon at a table with 5 prominent queen breeders from California. Their jaws were on the table. Their breeder queens had been mating with mongrels hanging out in some distant oak tree. Since then mating yards have been arranged with mating nucs in a center yard and drone hives set in a circle around and about 3000 meters away from the mating nuc yard. So if you are raising drones in your yard for genetic diversity, who's queen are the mating with? Was Taylor's study correct?