Most people only bathe their chickens before they're going to show them...
I've bathed Slifer and Obelisk before we went to Chickenstock.
I use baby shampoo and rinse well. Blow drying is fine for them too, just not on HOT.
Most of the time, dustbathing is fine for them...
Raven, SpottedCrow is correct. the natural way for chicks to bathe is with a dust bath. I kill 2 birds with 1 stone by adding some 5% sevin dust to the dusting area, the birds not only get their shower but also dust for vermin which eliminates the stressful need to gather the hens up for dusting, they get it done on their own, keeping it simple and also vermin free!
It was 82 degrees today and some of the chickens got together for some sunbathing they are going to miss the garden when I shut the door oh well they have other places to bathe.