can chickens eat

Apart from the very common foods, what else can chickens eat?Apart from the very conventional foods, what else can chickens eat? For example Olives, Collard Greens, Black Beans?

I’m not sure what these lines are! We live in Florida. I noticed this morning that my chickens are picking up these red flowers when I fall off the vines and eating them😲! None of them have been sick and they’ve been out here for a few months! Thank you guys so much for all the help y’all have...