I read in an online auction site about someone giving away two light sussex chicks (roos), 4 weeks old. Hey...they same age as mine, and no incest. No interbreeding. I got them home, let chicken little and her 10 chicks out for a feed and dropped the new roos out of the box. They mixed in immediately. They did look around for thier mom, cheeping a bit, but my chicks ignored them. Chicken Little looked sideways at them, as if to say, "My you've grown". The two in the front.. After 30 minutes I put them back into thier run and watched them again until they ALL went to bed. Top middle, and on the roost. Standing on Chicken Little, "Are you my new mommy?" This morning all are eating and wandering around as if they have always been part of the flock.