Sussex19
Free Ranging
Many things were different, in that the chickens would have been part of a farm, with other animals.How would old farmers raise their birds? Commercial feed has not been around very long. My grandparents raised lots of healthy chickens. They only supplemented with corn. Their flock thrived.
They all work together, and the chickens would have got a bit of what ever the other animals got. Also, they wouldn't have laid as many eggs.
I think they way the OP is doing it, it could have a very good outcome. Or not of course but they won't know till they try. And I always like to learn more about different feeding methods.