Normal bee stuff, its called bearding, this is not a large example but the same, there just doing there thing, might be full already, real big swarm, and no were for them to go, I would pull that down and put it were you want it, check and see it they got room, heck could be so large you need another hive body, never know.. LOL
LOoks good to me tho, wish I could catcha swarm. Congrats on the swarm.