My birds love greenleaf or romaine lettuce, (don't feed them iceberg lettuce, because nutitionally is it pretty much nothing but water)and they will also eat carrot and broccoli. Some of them will nibble on orange and apple, but they don't all like it. Just about anything is ok, as long as it is washed really well and is fresh. Greens especially need to be kept fresh. The only thing I know for sure that is bad is avocado.