How lush do you suppose that pasture is up in Maine at the end of the season? May look good but it’s probably played out nutritionally.
They are all eating a very large amount of the Timothy/orchard but that may mean it’s nutritionally lacking unless they are hog fat on it. And do you do the feeding? Are you there at each feeding? Have you actually weighed the hay or just going by what you are told or guesstimate? Barns are notorious for short feeding, not usually on purpose but because they don’t weigh anything. Sometimes on purpose to save money…and they are all nice and sweet and really care for your horse. Not.
Im with Lady E, up the alfalfa, lose the junk unless you want to keep spending on it. Your money. Soaked cubes are the best choice in boarding barns, maybe 8 lbs split into 2 feedings a day. Don’t think he needs any concentrates with upping the alfalfa but others feeding alfalfa aa a primary forage add just plain oats in small amounts with active show horses.
I’m a KISS fan in feeding, the fewer things added to a high quality forage based diet, the better and you will have fewer digestive issues.