A store bought feed is going to be the most nutritious, and accurate food you can give them. While the foods you are feeding your hens are safe for them, the diet is extremely limited, and low in fat and protein. Plus, while millet is higher in protein, it is not a complete protein. It does not contain lysine, which is a critical protein component for hens. Honestly, you'd be saving money in feed buy buying layer or all-flock feed, and you'll have healthier chickens overall. Healthier eggs, too. I can go on and on about mixing your own feed, so much so that I've spent months compiling a blog post about it to record some of my experiences. (
https://humble-hills-farm.com/2020/...nd-cost-calculator-for-homemade-chicken-feed/) but even that post is not comprehensive. In my opinion, store bought feed is going to be the easiest, safest, cheapest, and most nutritious feed you can give your flock.
Edit: I calculated approximate ratios for your feed. If you did 3 pounds millet, 3 pounds barley, and 3 pounds of corn, you're giving them only 10% protein (and an incomplete protein at that) and 3% fat. The need a diet of 17% protein and 4% fat.
Actually, those grains are high in carbs, very little fat, and millet is not a complete protein either.