You may have to mix your own, or get your local feed mill to do it if they can't order in some. For a long time we let our free-range birds eat swine feed. It was ground corn, protein pellets and added vitamins. They loved it and were free-ranging all day long for what they needed. I am sure the mill would work with you on protein % and what you wanted in there. Just would not be crumbles or pellets, but actual grain. My husband's grandmother lives in Romania, her chickens only get shelled corn, and what nature provides them. They do okay. You might run an ad and get some other interest in ordering a larger batch, but don't get too much as it will loose vitamins over time. Maybe you can sell the extra to someone if you have to order it online.
HenZ