What should I feed my backyard chickens every day?

[FunkyMonkey]

I recently started keeping a few hens and want to make sure I am not giving them the wrong food. There is so much conflicting advice online about grains, kitchen scraps, treats, and complete feed that I am not sure what should actually make up the main part of their diet. I would rather get the basics right from the beginning than correct nutritional problems later.

What would you recommend I feed my chickens on a daily basis, and how much room should I leave for treats or scraps?