I have a QH mare that I bought about a year ago. She has been on a regular wormer with a dose every 6 weeks beause she was severly wormy when I purchased her. She will not gain weight; she hasn't gained a pound since she has been with us. My vet keeps telling me to worm her and feed her, which is clearly not working. She is on senior feed, hay, and access to all of the grass she could ever want. I have two paint geldings and a quarter/pony gelding and they are all fat and happy, but my mare just looks so pitiful. I have had people ask me why we don't take care of her like we take care of our other horses! Any suggestions???