Thanks guy's, I've treated both hens and the coop, and all their combs etc are still nice and red,( I read they go pink if the hens go anaemic)There are no mites under the scales(as I'm forever checking). I'll keep treating both hens and coop anyway just in case.
Thank you again, from what I've seen on this site so far, you two look like Legends in the Chicken World.........