I would avoid bread, its not only empty calories but can cause yeast infections in all ages of birds. Grass is really not good for chicks either, you would be better off with Alfalfa leaves which are a healthy grass loaded with protein and minerals. Clover is fine. Chopped apple or veggies would be OK too but definitely limit these side foods to once a day and a very small amount, chicks fill up fast and the need to eat their starter feed. Make sure to sprinkle these side treats with parakeet sand for grit, sprinkle it as if you were salting your food, this will be enough grit.