Can a horses growth be stunted from a young age by underfeeding?

They can. When the youngster is not receiving the correct nutrition they can't grow like they should. Not only can it stunt the height of the young horse it can cause damage to internal organs that may effect his health throughout his life. It is so important for young horses to get the correct amount and type of food, hoof care, vet care and of course love and training from his people. It's a very big responsibility but when done right you have a happy, healthy, strong young horse that will give you many years of service and companionship.