My chickens get pretty much anything in my fridge that's a little too old for me to want to eat it anymore (never spoiled, of course). They don't go absolutely crazy for everything, but there's very little they just won't eat. Veggies, cooked meat, pasta, they'll eat it all.
I think their favorite is any kind of bread. I love giving them soft tortilla shells that are going stale - it's somehow amusing watching them peck holes in them. Cooked rice is also always a hit.
Last summer they really enjoyed watermelon rinds. They also got any of the garden zucchini that started getting blossom end rot - they made pretty quick work of them (I usually had to break the zucchini open so they had somewhere to start).
Yesterday they got a container of coleslaw - I was surprised how much they seemed to enjoy that!