Depending on how much handling a chicken has had depends on how still they stay while giving them a bath. If it's a spooky breed two people might be helpful - one to hold the chicken's wings down from flapping and one person to do the shampoo. I have bathed different breeds of chickens from spooky Ameraucanas and Leghorns to gentle Silkies in a deep sink with lukewarm water and baby shampoo. Sometimes I fill the sink halfway with warm water if the tush/vent is very dirty and gently patiently work the mud/poo/gravel out of the feathers - sometime I use 2 or 3 shampoos and rinses to get the gunk out. Most of the time it is only the tush that needs a quick cleaning in which case I just run the warm water constantly from the tap over the butt. However, if the head or crest or beard needs cleaning I don't use water directly on the head but use a very wet soft washcloth to get to the scalp -- that way water doesn't run into the nostrils or throat. I use baby shampoo to eliminate possible eye irritation in case the chicken splashes everywhere although some owners claim they use Dawn soap. I prefer the no-tears baby shampoo which I found cleans just as well as Dawn. Afterwards I bath towel wrap the chicken to prevent chill. I have a towel ready with extra paper towels lining it for extra absorbancy because that chicken is going to be dripping excessively out of a rinse and the paper towels are very absorbent. Then we transfer the wrapped chicken to a platform where we start to blowdry them with a hair dryer on low warm. Chickens seem to like the warm gentle blowdryer setting except maybe near their head. Silkie baths are relatively fast because their fluffy feathers wash and dry fast. Fluffy birds like Ameraucanas or sleek-feathered birds like Leghorns can take much longer to dry. I love giving my Silkie baths because it goes fairly quick but I dreaded having to bathe our heavily under-downed Ameraucana because it took so-o-o long to dry her heavy feathering.