So much to learn about chickens. How do they keep clean? Turns out that rolling around in dry, dusty earth does the trick. Here's a picture of my girls, from left to right: Stephanie, Michelle and Sandy. The former two are in dusting spots, Sandy is not, although she has a spot, too. You can see a couple of spots around them.
Chickens really don't need water bathing, unless you're showing them or they get into something messy. From ChickenKeepingSecrets.com:
Hens love to give themselves dust baths. Roosters aren’t as likely to enjoy a good roll in the dirt though. When it is warm outside, your hens will look for a new place and scratch down until they reach nice, fine dirt. They’ll flop onto their backs, close their eyes and just roll around. They get the dirt way down into their feathers until it reaches their skin. When they are done, they’ll shake it all off and feel fresh and clean.
Apparently, dust bathing cleans them the way water bathing cleans people. Also, the stuff they kick up makes breathing difficult for any parasites that have latched onto the chickens and the parasites die. Nifty.
The girls seem to enjoy using the spots in the picture the most. Occasionally, they'll dust a little in other grass/dirt areas (the grassy areas soon turn to dirt areas once the chickens start bathing in it) and mulch. They flap around in the dusting spots and they might set a while, especially if the sun's shining.
For various reasons, some people make dust baths/spots for their chickens. The area the chickens have access to might not be appropriate for dusting, e.g., it might be too wet. The general recommendation is to use dry, fine material, e.g., a mix of sand, fine dirt and wood ash. Some people add a bit of diatomaceous earth to help with pest control.
The girls seem to enjoy the dusting spots they've made for themselves. I may have to provide something for them over winter when the ground is harder and stays wet and cold, but for now I'll let them enjoy their moments in the sun.