I keep hearing you can give your chickens "table scraps" but I know there are certain things they can't have (certain veggies, etc). Just how much of the "scraps" can you really give them? Like can I scrape the plates into a bowl for them, leftover hamburger and all? Or just the leftover veggies? Pasta? Rice? Sauce? I would be happy to supplement them with this (would probably save some money), but I'm leery of *just* how much they can have. Help please?