Someone said on here you "owe it to the horse" to find the root of the problem and try to fix it, and I beg to differ. You do not OWE that horse anything. She is a sourpuss sow and you got tricked into buying a problem horse in a bad market. Sorry about that, and shame on the sellers. All that being said, horses are bought, sold, traded and givene away every day for any number of reasons, lack of time, financial pressure, outgrown, unfit for purpose, horse diminishing usefullness, dangerous, too small, too big, to fast, too slow, wrong color, thin mane, too many socks and blaze too big, navicular, you name it. DO NOT for one second think you are morally obligated to feed for one more day a dangerous, bad tepmered, ill mannered sow of a mare. Adios amigos is all I would say about that. I personally would put her down, in this market and just eat the loss.