Bathing a chicken can be easy. Or difficult if the chicken is not digging the bath experience. Fill a dish tub or bucket with warm water. You may need two or three tubs/buckets to get all the soap off. Dunk him in the tub and let him soak so his feathers get wet through and through. Once he is soaked through, give him a scrub with a baby shampoo or another clean rinsing shampoo. Suds him up, scrub the dirty places, then start rinsing him off. Once all the soap is gone and he is clean, towel him off and grab your hair dryer. I use one the has three settings cold, warm and hot. I use the warm setting. If your dryer only has one setting, hot or hotter, then you will need to hold the dryer far enough away from him so he does not get too hot. He will wiggle trying to get away from the heat if it's too hot. Start drying him off. Once he is completely dry your done with his bath!
This is also a good time to trim toe nails, spurs of needed and to also give his legs a good coat of vegetable oil to help control scalie leg mites if he has those. Just warm up your veggie oil to a little above room temp. This helps make the oil more spreadable and spread it all over his legs and feet rub it in a bit and voila! A clean and tidy bird! Hope the helps!!