My hens started pecking each other (and themselves) to the point where they do not have any feathers on thier butts. Some have some blood. The old timer at the feed store told me to put pine tar on there butts and it would discourage the pecking. I did, they are still pecking. I also read to try adding viniger in thier water as they may be diffiecient in some minerals or vitamins. I just did that. Any ideas? They are about 10 months old and are laying great.