I have noticed that our horses get fatter on grass than hay. Odd. Hay is generally really just dried grass. Pago especially. He can have 24/7 hay and still stays leanish. Put him in a good grass paddock and he goes rather round. Dizzy gets fatter on grass than hay. The hay is good grass hay. Made from the same grass they would be on in a paddock. Any ideas why? Could they actually eat more grass because it tastes better?