Why new dust bathing spots...sign of mites or fleas?

[Daisy8s]

I check them regularly and have seen no signs of mites or lice, but seeing them frequently move to a new spot was making me wonder why. It is pretty funny to watch. They move en masse to the new spot, take turns bathing, and then lay down in a communal huddle to take naps. i guess all that digging and rolling and flipping of dirt just plain wears them out!