I would assume you would do it just like a chicken only depending on your bird with a bigger tub LOL! I have read that to bathe a chicken you can put them in a tub with some dish soap in it and make it like a bubblebath! Then you rinse them real good. I am hoping some of our turkey experts can help you.
My turkeys would never stand for a water bath. The chickens are much easier to control and handle, so I am curious how well it goes for you. Keep us posted!