Sorry, I realise I didn't answer your other questions!
It's best to provide a combination of grains, as well as a source of calcium and protein, as chickens are omnivorous (and they LOVE meat!).
Corn fed. I think that might work for commercial strains of meat birds, but tends to put fatty deposits on other breeds. I also think it makes a blander flavoured bird if you over feed. Best to provide a mix of grains over the course of their lives, and if they're a growing bird, protein and calcium (though not as much calcium as a layer should get) is important. Calcium can be made available in the form of crushed eggshells (which is what we do) as well as oyster shell grit.
Kitchen scraps and corn and a few other grains should be adequate for chooks, as well as all the compost-type material you have access to, for them to fossick through. It helps it break down as they scratch through it, as they add their own fertiliser to it.
Corn can be easy to grow, but it also sucks nitrogen out of the soil, so you will have to be sure to replenish it after each crop (a good nitrogen-fixing green manure crop would be a good thing to sow when you aren't growing corn, and then turn it back into the soil).
I hope this isn't too disjointed, as I am feeling rather muzzy this morning, it being autumn and me wanting to just pull my head in for the winter and hibernate!
Cheers
Andrea
NZ
