Just as you wouldn't give a human infant steak, you don't give baby chicks food that is too large and tough to digest.
Even before you think your chicks are ready to eat seeds or any foods high in cellulose, you need to provide them with chick-size grit to grind up the tough foods in their gizzards. You can buy it at the feed store where they have the chick food.
But you still want to wait until your chicks have mature digestive systems before you task them with tough to digest foods. I would wait until they're at least four weeks old before feeding seeds and other tough foods, and then only if they have access to grit.