Thank you both for your advice and patience as I learn.
I checked the entire hive yesterday -- took every frame out (very carefully) and looked for a queen. I couldn't see her, but I think she's in there as they got increasingly agitated the closer I got to the middle of the hive.
What I did find was a lot of capped brood with larva and baby bees crawling out of some of them as I inspected. I got so caught up in looking for the queen I didn't notice if there were eggs or not.
There's also a lot of honey on some frames and other frames have very little comb. One frame had two layers of brood comb with queen cells attached. The bees were working both sides of the comb and leaving the frame empty.
I found a few supersedure cells and a bunch of closed swarm cells, 10 in all, and 4 cells that look like they've been opened, ie they no longer have an occupant. I also saw some emergency cells too, they were open with nothing in them.
I read this PDF @Dee posted: http://www.wbka.com/wp-content/uploads/2013/06/There-Are-Queen-Cells-In-My-Hive-WBKA-WAG.pdf
and I'm still unsure of what to do.
Should I split the hive? Destroy the swarm cells?
There are a lot more bees that I would expect at this time of year. The hive is very, very healthy. Maybe too healthy. I set a trap box up with old comb in it just in case they swarm again.
Thank you again.