My doe, who kidded in march, has very dry skin and is losing hair. especially her tail and topline. we gave everyone copper bolus 5/24/20. but we didn't get it all the way down and she chewed hers. they get free-choice mineral. I've given 2 rounds of ivermectin pour on. but she still has extremely dry skin, and almost has bald spots. none of my other goats show any of the same problems. any ideas what wrong and what I can do??