Never never and never feed your chickens chocolate. There are other foods that aren't good for them like avacados, dry rice, citrus, candy, dry beans, salty foods, onions and any kind of junk food. My birds do love cheetos and yes I give them one or two, but not very often.
Your incorrect on some of you "food".
Citrus, Dry Rice and some Dry Beans are just fine for chickens.
As far as that go's so are Onions but they tend to intensify the sulfur in the eggs.