It's not for every horse. How much hay do they get ? Quality of hay? I had my horse on a progressive rb with one of their weight supplements. I couldn't keep track of the hay at my barn but it is good quality hay and I don't think he got enough for a horse on a rb. I gave up on the RB because he was just too skinny for my taste and switched him to TC senior. He got much healthier looking within a few months.