Mare that wont eat for 3 weeks?

Okay, she is a 24 yo arab. healthy until Oct 18th when she took her last bite. The vet came out Sat Oct 19th. she was lying on the ground, not rolling,k normal temp, respiration, bp. checked her teeth. SLIGHT ridges on upper right but nothing at all to be concerned with. @ days later she had shallow breaths, respirations, calle dthe vet out again. they administered, pain IV meds, sedation, full exam, rectal, mouth recheck, administered oil (for possible impaction) along with epsom salts after emtying the stomach. They retrieved only 2 quarts of water out of the stomach (5-6 is cause for concern). so the stomach is not emptying perfect but no alarm. Bloodwork up done. NOTHING shows, infection, no liver / kidney failure, only shows dehydration. We have given her IV potium (since shes not getting hay in her) and we pumped her tummy full of 2-3 gallons of water. We have fed her seperately since \then from our other horse, BELIEVE mewhen I say she hasnt eaten. two weeks in she took one mouthful of hay, wont eat grain, sometimes sucks on the water we put in it to entice her. Like I said earlier she wont even eat her favorites. She has lost weight a bit looking like it here in week three. She conserves her energy lots. she looks at the hay, sticks her head in the bucket like she desires to eat,m but I even had to shove the watermelon in her mouth once to get her to chew. The vet is at a loss. They had one just recently that stopped eating for ane whole month then just started up again. We believe if she doesnt start she either has a lipoma surrounding her intestines, or a stone that is making her uncomnfortable.. Our goal now is to ENTICE her to eat.. ANY IDEAS??? BTW I cant figure out how to answer you all back without writing another question... help