Perhaps a little spot of paint, on the feathers of one? Personalities will continue developing. My 5-6 wk old Blu sapphires already have one at the top of their pecking order. It is difficult to tell when they look the same.My 8week old Barred Rock look identical so I can't tell who is who. I have a couple that are friendly but the others are still flighty. Time will tell I guess. I did buy the different colored zip ties with the charms but still a bit nervous to use them.