I feed the horses grass hay year-round and the chickens do eat some of it, but mostly they like scratching through the loose stuff on the ground to see what yummy bugs might be hiding underneath. When we bring in a new load, it gets "inspected" by several of the girls and the younger roo before we have a chance to unload it, it's funny to see a ton of hay on a truck covered in chickens!
Be sure they have acess to gravel or grit, either as free range or supplement and you should be fine.
Be sure they have acess to gravel or grit, either as free range or supplement and you should be fine.