They would like seeds and live mealworms at this age. In my experience chicks don't go much for greens until they're older but all birds are different. Be sure to offer chick grit if you give them anything but their feed though.
Scrambled egg yolk, canned corn (might want to slice the kernels in half to start) spiders, bugs and worms, spinach or other veggies cut very finely, little pieces of fat from the skin off a piece of salmon.... chickens will eat a lot of things.