I have a friend that I would like to help but don't have a clue as to do. I personally own quarter horses and they are very easy keepers. She owns thourobreds and standardbreds and most of which are slightly under weight. I know that she feeds them good quality hay and supplements them something (not sure what), but they never seem to gain any weight. Is there anyone else out there that has experienced this same issue and is there anything that I could suggest to her that might make a more significant change in their weight gain? Any information that you can suggest would be greatly appreciated!