I give scratch grains, veggies, herbs, and occasionally I cook oatmeal for them in winter, I'll even make them pasta because I spoil my chickens or pop them some popcorn.

They adore grapes of any color but seem to really like the green variety, and I also give them almost anything: watermelon, strawberries, pears, apples, nectarines, tomatoes, and a bazillion of other things I can't remember right now. Of course, my chickens are so spoiled they usually turn up their noses to veggies like lettuce and other leafy greens, though I found hanging it can sometimes encourage them to eat their salad before their dessert, lol