I have been getting my hives ready for winter slowly, taking off suppers and extracting, reducing entrances to a few inches wide. The other day I took a super off of my smaller hive, reducing it to two deep brood boxes. I was going to look farther down, but came across frames of brood in the second box. I took the super back to let them clean it and found LOTS of bees at the entrance. Hovering as if they were traffic jammed to get in. I thought it might be robbing, so I took a closer look, but saw no fighting, and A LOT (15) of bees with butts in the air spreading nasanov scent. LOTS of the bees were bringing in pollen. I added the extracted super and left them as I have to get to work. Any ideas about what this all about?