Scratch is a treat, to be given in small quantities. The "old fashioned" way to feed them is a little scratch or cracked corn, table scraps, and plenty of good forage, with grasses, bugs, bushes and trees, etc. Most backyard flocks are in small runs and need a formulated feed like layer.
Usually the progression is starter to grower to layer, for a laying flock. You change from starter to grower around 8 weeks --- but don't throw any away, just mix them or feed whichever you have. Where I live, they sell primarily a starter/grower combination feed, so I feed that til they start laying.