So the Justin Rhodes formula has 20% peas - not something I have found locally and super pricey online. Anything I could substitute? Or any ideas where I could find cheaper?That's a list of potential ingredients, not a recipe. So no one can tell you what the final results will be. What they can tell you, and what I said on the first page, is that you can't make a nutritionally complete healthy feed from those ingredients. For reasons I explained on that page.
Making a Homebrew chicken feed is not an Endeavor to be lightly entered into. If you know what you're doing, and you are not doing it on Commercial scale, you know enough to not want to do it. If you don't know what you're doing but have specific needs or unusual circumstances, start with Justin Rhodes formula then come here for help adjusting it to your needs.