You might want to take a look at Harvey Ussery's book and website. His book is the best "modern" book that I've seen on a more natural approach to chicken keeping. There is a whole section on his website about feeding the flock which is also in the book. Definitely worth reading.
This link is to the section on feeding but there are a lot more articles on other items.
Here is the book.
This article may be of particular interest.
I've read at least some of the information at the link before ... I was extremely put off by the tone he took with the person writing in for advice in Part One of the Making Your Own Feed section. So I remember it being hard for me to keep reading.
I'm going to read it all again ... I'm in the process of reorganizing stuff here ... One of the things I'd like to change is my feeding program ...
Thanks for reminding me about this resource.