Why you don't want a hive to make their own queen

In the spring when hives swarm. Some beekeepers think they will just let the hive make their own queen. During the month of May in Minnesota, our hives typically don't have widespread drone populations, by early June there usually is good drone population everywhere.  Because of low drone populations in May, the odds of a queen getting properly mated are not great. Just because their is a large population of drones in your own hives has no bearing on a queen that you want to get mated. When a queen goes on her mating flight, she will fly further away from the hive than the drones in her own colonies. This prevents interbreeding with her own offspring. So a beekeeper is depending on other beekeepers near them to have a large drone population to mate with their queen.
But in the springtime, more than proper mating, it is the time it takes for a queen to lay and the how long it takes for new bees to be able to forage.
Lets break it down:
So let's say the bees swarm when the swarm cell is capped.
6 days to emerging queen.
7 days until a queen can go on a mating flight
7 days approximately until she starts laying eggs
21 days for the first egg to hatch.
22 days until that first bee can start flying to forage.
 More than two months from start to finish. This means if a hive swarmed in mid May for example and a beekeepers decides to let them make their own queen and if the queen was mated. It will take to almost mid July before the prodigy from the new queen can start  foraging for nectar and pollen.
Even if a hive swarmed, but a beekeeper was able to remove all the swarm cells, installing  a purchased, and already mated queen, will take around 18 days off this time frame. But before swarm cells are removed make sure a queen is available for purchase.
When a hive swarms they do leave behind capped brood and house bees that cannot fly. The capped brood will emerge and the house bees will mature and age. They will forage when they come of age. But the population has suffered greatly from the swarm and a good honey crop is usually not in the cards.
So watch your swarming, cut the swarm cells before they are capped.