At my old house I had three chickens. I let them free-range the yard (1/3 urban acre, fenced) and fed them in the morning. I fermented their feed (mixed grains) for three days, four bottles rotating. I put 1/3 cup of dry grain mix in each bottle. 1/4 cup was too little, 1/2 cup they usually left some. If it dried out I just dumped it and they'd scratch it up.
I plan to do the same for the chicks I have now.
Feed made of barley, wheat, oats, flax, and dried duckweed. Sunflower seeds might make a good substitute for flax, or an addition if I find prices are rising. Anyway, it's something I can grow myself.