My 20 yr old QH dropped alot of weight this winter and despite my best efforts he hasn't really been able to gain it back. He gets free choice grass hay. Although it's not the best quality, it's the best I can do right now. He gets Triple Crown's Low Starch feed and the last month I've been mixing beet pulp in with it. He's been getting Grand Vite, SmartFlex Sr., and I recently started SmartGain 4. He's wormed regularly and was fecal tested 2 weeks ago and it was negative. He's also blanketed. He has many allergies, especially to alfalfa, so I cannot give him alfalfa pellets, hay, or cubes or any supplements with alfalfa in it so that rules out any senior or complete feeds. He's mildly allergic to timothy and rice bran so if I can avoid them I do. I would like to try adding an oil to his feed but don't know if corn, canola, or vegetable oil works best for weight gain. Or maybe another oil I don't know about? Any other suggestions would be great.