My sister in law claims to know someone who has a huge outdoor flock and feeds their chickens nothing. Bro. can't understand why I "waste" money on food. He doesn't know what it's like when they fly at you screaming when you're late with the feed, and the fights that can occur. I suppose wild chickens subsist on whatever they can find, and I vaguely remember an article in a mag. (Mother Earth ?) about someone who got huge loads of scraps delivered from restaurants and dumped to compost and be eaten by their chickens. I think it said they lived on that, and whatever they foraged.