For the rest of its life, as long as it's given water and salt as well. Horses are naturally made to live on grass and hay, and will have no problem living on it for all their lives.
they graze on grass and hay
grass & hay
Hay
a white horse eat hay and grass
Hay as well as horse feed and grass.
mainly hay or grass
I'm not familiar with this breed but if it is equine it most likely eats grass and hay.
Orchard hay is a type of grass hay grown from orchard grass. This type of hay is excellent horse feed, but can be fed to most any grazing animal.
Horse fodder is basically the food a horse eats. Hay, chaff, grass.
A wild horse mostly eats grass ,hay and berries.
A horse eats grass or hay and no animals.
It depends on the horse. Ask your vet to see what's right for your horse(s).