I have this activity all of the time on my hives. I don't really consider it bearding, it appears to be younger bees transitioning to foragers, un-needed inside the hive, but not quite ready to fly. If you watch them, eventually you'll see them do a short looping orientation flight and then maybe head back inside the hive after that. In my case, (we call them porch bees), the seem to be wash boarding (cleaning) the landing boards and possibly act as guard bees for any robbers. I think it's a sign of a health population.