Only give the cracked corn for treats, if they are free ranging you can give them a little to entice them into their coop and to increase body temp when it is cool. Feeding a diet of cracked corn is actually more expensive than layer or maintenance feed. They will eat more of the cracked corn then they would the other, in the long run costing more or the same.
I feed my penned birds no scratch at all, strictly layer, starter, and maintenance. I give them scraps from the produce dept when I can get them. Free rangers get a little scratch of a night before roosting to increase their internal temps. As the bugs disappear with cold weather I will give the same mix for penned birds in the morning to get them going.