What do you feed to enhance feather color and shine?

I am new to chickens, but I would imagine letting them free range in your yard to let them eat all the bugs they can find (especially in the compost!) and all the greens they want, plus supplementing them with a high quality feed would be the best way to get a healthy looking chicken. I know my cats never looked healthier than when I was feeding them a raw diet. Right now I am feeding them a grain-free "2nd best to raw" diet (mainly due to 1 cat having a grain allergy) and they are very shiny and healthy. But when they were on raw, I had people stop and ask me how I got them so shiny when they saw them in my front window! For real! Natural diets as close to what they'd eat in the wild is usually the healthiest way to go. But since our chickens are confined, we do have to make sure to feed them food and not just let them find their own for all of their calories.

 

Black oil sunflower seeds and/or flax seeds.