I have been busy researching how to bathe my chickens properly, I have 3 silkies who could use a bath! I need advice on what kind of soap is safe to use! Something that won't dry out their feathers because of removing the oil. Also any advice for bathing a silky will be appreciated! Thank you! By the way- I have 2 white silkies and a black one, I want the white feathers to be all white again!