I get a couple of bags a week from a local church's kitchen after Wednesday night dinners. Carrot peels, lettuce and celery stumps, cabbage remains, onion remains, etc. etc. etc. Anything I should NOT be throwing to the chickens?
All those things sound fine, but if you ever come across citrus fruits or dried, undercooked beans, you should toss those out. Also avoid avocados. And obviously, they shoulnd't have sugar or anything salty.
I've heard that they shouldn't eat potato peels, but I feed mine some everyonce and a while, and they are a healthy, lively bunch of chickens! I don't think there's really a problem with those.
I'd think in terms of, what would I eat? Even in a bunch of discard veggies, there are good parts, there's some scary mold etc so just don't feed 'em that part.
Our neighbor gets stuff for his sheep just about daily, and sometimes the stuff he gets is good enough that we humans skim off the best parts. You can often ask for, and get, rottsy veggies from your local market, handy to know if you're really poor or raising chickens (or both!).
Chocolate's not good. In fact we humans are kinda weird in that we can eat it and enjoy it.