I have a 5 year old ArabX. In the beginning, on rough board, she was eating a three-quarter scoop of Triple Grain Low Starch 2x a day, 6 flakes of hay, and had very little turnout grass to eat. In December, I moved her to a full-care facility. In this new place, she gets a scoop of a "custom" Blue Seal feed (designed for reiners and barrel racers) 2x a day. She gets approximately 4 flakes of hay, and is on lush turnout for 7-8 hours a day. She is worked 4-5x a week. I have noticed a slight change in her weight, but she is still considered a healthy weight, and no one would classify her as being over-weight. Problem is, she is getting a cresty neck, and it seems to be getting bigger. I spoke to my vet and he didn't seem overly concerned about a chance of metabolic/IR once I suggested it.
Should I switch her back to a low starch grain? Adjust the hay or turnout time? The latter is something I would rather not do, but what do you think? She is a small horse. She weighs anywhere from 930-1000 last I weighed her, and stands at 15.2.