>When a Queen takes off for her mating flight I'm assuming the drones she produced also follow along with other drones in the area
No. The drones from her hive tend to go looking for a DCA and they hang out there. They are not following their queen. Other drones are not following her either. They are flying to the DCA and waiting for a queen to show up.
>however I did read once now that I think of it that other drones from other hives actually move into other hives so maybe it's not that big of an issue as I might think?
Drones drift shamelessly. But they do not follow the queen, so it's a non issue.
>Second part. If I have other hives (My own in the yard) will she more likely breed with those drones or will drones from several miles away get there in time as well? How long is her flight? WIll she travel far if other drones from hives in the yard go after her?
Drones will not go after her until she reaches the DCA or at least crosses a flyway on the way to a DCA at a low enough altitude. Queens tend to go to a further DCA than the drones so the drones from her yard are likely at a different DCA than her. She is also unlikely to encounter them on the way as she flies higher than the drones so their paths won't cross on the way.
>Drone eggs fertilized by a queen's brother will be removed from the cells by the workers. Don't ask me how they know, but they do.
They know because they can sense that they are diploid drone eggs and are therefore male even though fertilized.
>I went to a queen rearing class earlier this year and it was mentioned a queen will not breed with a drone that is within four generations of her.
I don't think that is true at all. I think she will breed with drones from her hive IF they were at the same DCA and they were fast enough. It's just the deck is stacked in favor of it not happening. I don't think there is any guarantee it won't happen.
>I have a hive with unhatched swarm cells and the population of dissimilar drones is noticeably larger.
Some are probably from adjacent hives, but also the drones are haploid and if the queen has both black and brown (and maybe even cordovan) color genes, her drones could get either of those two genes and since there is no matching gene to suppress it even the recessive traits get expressed at 50% of the drone population.
> I think it is kind of cool drones from neighboring hives are accepted for sleepovers.
Not much of a sleepover since any queen there is very unlikely to mate with them...