I feed mine cracked corn every morning when its cold, and sometimes in the evening if it is really cold at night, but cracked corn is NOT good for them in the summer when it is hot. In the summer afternoons when it is hottest, I chop up frozen peaches, or grapes or blueberries. I give them one big hunk of frozen watermelon, frozen corn, corn on the cob is a big favorite, frozen peas, chopped tomato, any kind of chopped lettuc, celery leaves, left over scrambled eggs, chopped hard boiled egg, chopped cucumber, (the seeds are good for worming), carrot peels. In the winter, I switch it up with left over cold cooked rice, bread heals crumbled, corn tortillas crumbs, cooked oatmeal with a little bit of raisins.
Always a generous supply of grit and oyster shell. I have 6 different breeds, and never had a sick chicken, and they all look great and are good layers. However, everything in moderation. I usually never "treat" more than what will cover the bottom of a pie pan with one layer, usually once a day, for 5 hens and a roo.