I was watching some film footage on TV recently, where elephants were covering their hides in mud and when they had a good coating they would leave the watering hole, then finish off by having a dust bath.
It didn't seem clear why they did this but it reminded me of humans using talcum powder.
My chooks used to love a dust bath. We have a few pheasants in the garden who do this in the borders. I know birds do it to help with pests and I used to help them with a bit of diatom.