Today while near my hives,  I found myself in the middle of a swarm of bees
about a big as a bus.  They were just milling about the hive.  It was very
windy and at times would be blow 50 or 60 feet away then return to the hive
area. I guessed that they were getting ready to leave so I prepared to follow
them till they clustered some where.  after 30 or more minutes, they
clustered on the front of their hive and in 10 more minutes,  reentered the
hive and all has been business as usual the rest of the day.

What did I see?

Was it a queen breeding?

They streamed out by the thousands and then returned.

During the time that this happened,  the adjoining hive stopped all activity.
 After it was over they went back to coming and going as usual.
Tomorrow I will split them and wait queenlessly for my new queen.