Charlie, you might take a look at the BREEDING FOR PRODUCTION thread and check out what my dad uses. You might have access to much of the same ingredients for protein as he does. I can tell you, what he does really works. He's set up for his method in a big way. I don't have the time or access to some of the 'raw materials' as he does nor the machinery but If I were breeding and keeping as many birds as they do, I'd improvise because it saves bunches of money.
The one thing I'm considering to copy is finding someone who butchers their own beef and try to get the contents of the stomachs. That stuff is partially digested and I've seen his birds out pecking at that stuff when the temps were in the teens and below. It has to be good for them.
Turk