This is a good debate. I'd like to add something I haven't seen mentioned. Grass isn't particularly nutritious for an omnivore like chickens. They prefer and benefit from tender greens like forbs. Tall grass is too fibrous for them to easily utilize.
Clover, alfalfa, buckwheat, peas, beets, radish, etc. are much more appropriate forage.
Clover, alfalfa, buckwheat, peas, beets, radish, etc. are much more appropriate forage.