Have had several horses that did this when I got
them. One was so bad that the previous owner had sold it for that
very reason. After feeding apple cider vinegar on the little bit of grain
they got, the chewing completely stopped. Vets, any reason for this working?
Even worked on one that "ate" my car when I first got her. (That made for
some interesting conversations with people before being repainted. Some
even thought all the marks were from cougar claws).
oregon (and yes, I have had a cougar in my yard)