Two of my chickens one barred rock and one ??? have large bare spots on their backs, quite raw but not bloody yet. I read on the site that pine tar would help. Went to tractor supply and the guy gave me ichthammol dressing said that would work. Well I have been putting it on them everyday and today I watched as they both started eating it off their backs. I am mad that I just spent $14 on something that did not work and my girls still have bare backs!! I noticed that my ??? chicken has lost lots of feathers in the nesting box. (I have 3 boxes for 8 chickens but they all prefer only one) HELP!!!!