The varieties of chickens we have today, which are selectively bred to trade off flavor/nutrition for mass/weight, require supplemental feed. They can't survive off grazing alone. The book 'The Dorito Effect', which I highly recommend, has a very good history on this. It's a good, as Angel Acres is, to attempt to reduce second hand linoleic acid in eggs by expirementing with different blends of supplemental feed. Maybe older varieties of chickens can be reengineered this way, over time.

If you check out edible acres chickens on YouTube, his setup is basically to take vegetable scraps, let the chickens pick through them, that composts in place, as he turns it, they eat the worms and bugs in the compost, then he gives them small amounts of organic grains from nearby farms. I think that seems to be as close to a wild chicken diet. But I do think using chickens as garbage disposals for our food waste is the best use of that resource, meat scraps especially.