Late and early Queens. A big part in the raising of good prolific queens is the mating. A poorly mated queen will fail prematurely. Mating is effected by weather, which we have no control over, but we can avoid times when the weather might not cooperate with the queen mating properly. The other major factor is drones. For successful mating you need abundant number of drones in the drone congrating areas. Keep in mind that drone take a minimum of 45 days to mature from egg to being able to mate. Queens can mate in as little as 21 days. Bees tolerate drones in the hive when times are good but will expel then when the honey flow slows down or stops, and when the weather starts to get cooler. There can still be drones in the hive because of drone brood hatching but the bee might be forcing the drones out of the hive before they have had time to mature. Another factor to consider is, when producing queens by removing the queen and letting them raise a new queen from young larva is it takes all most 30 days from when you remove the old queen till the new queen is back in the hive laying. Depending on the time of year the summer worker bees that can have a life span as short as 6 weeks will be rapidly declining and there may not be enough bees in the hive to support the queen in raising bees needed for winter. The best time to raise queens is when the hive and bees are in an expanding mode. More brood, more honey, more pollen, more bees, than there was the week before. Just like in late December and early January and the days start to get longer and triggers the bees to start laying brood as the days get shorter and colder the bees start to cut back on brood by plugging the brood area with honey and pollen.