We have to wash our chickens now and then, if they got under the roost at night and are all pooped on, or if they ate an egg and have it all over themselves. Once they had mites, and we used Adams Flea and Tick dog shampoo, it smells great. New Puppy smell great.
Blow drying a chicken can take about an hour. Free feathers dry in a minute or two, but when they're still attached to the chicken it takes a very long time, just be careful not to burn the very delicate skin beneath the fluffs, always keep your hand inbetween the hot air and the chicken as you try to fluff it, so you can stay aware of how hot its getting.
Our chickens like a bath and a blow dry. They hold their wingies out, lay on their sides as if in a sunbathing experience.