I second the raisins. It is by far the NUMBER ONE treat for my chicks...the go NUTS. If I bring the bag out the raisins came in and crinkle it (for the noise) the flip! The start flying around, clucking and peeping...trying to get to me through the run fencing. If they are out of the run, they will actually jump up at the bag trying to pull it from my hands!Try raisins, OMG mine go crazy for them. They also love love love watermelon,yogurt,spinach,scrambled eggs and beans. The list could go on and on.
Raisins must be the food of the gods for them LOL