chickens are like bird versions of goats. they will eat anything and everything. mine eat every scrap of plant greenery they can get their little beaks on. i would assume anything thats safe for human consumption is kosher for chickens too.
Garbanzo beans. I cook some dried beans up every week and they gobble them down! Mealworms, cucumbers, tomatoes, oatmeal, quinoa, cranberries, and they go nuts over some fried eggs.
This morning my chicks went medieval on some ants that got into the coop, when they were done with the ants they finished off the apple piece that they were eating.