Awesome dustbath pic! Looks normal to me!
We used to have a big snowball bush. The chickens would spend whole days underneath there. The best part was watching my big fat white rooster dustbathe. He would cluck encouragingly to the others, kick up huge showers of dirt and then peck at anything interesting that was unearthed while emitting excited clucks. He was so fat that he would dustbathe almost on top of his harem without noticing.
He was a big white bird, so after he dustbathed he was always a filthy, dusty brown color. He'd go skulking around the yard like the cock o' the walk, oblivious to the dirt clinging to his comb and wattles. It was hilarious.