To my knowledge, chickens lack the enzymes in their stomachs that ruminants have to break down the high collagen content in grass. They may have some bacteria in their guts that can break down and tear apart the grass, but not nearly enough to get substantial nutrients from it. I guess if you inoculated them with a strain of bacteria that could produce collagen digesting enzymes they could. No gaurentee this bacteria could survive in the chicken though. Ruminants have multi part stomachs that contain billions of bacteria and other microorganisms that they use to process grasses and often chew their cud so to say, as it is a long process to get good out of it.
I free range my cornish x but they still eat mainly their feed with just a bit picking at grasses.
I free range my cornish x but they still eat mainly their feed with just a bit picking at grasses.