I have two over 4 week old chicks, fully feathered and now out in the coop and run. I also have a 4 day old chick in the brooder in the coop. Today while I was cleaning the coop, the 4 day old was making a big fuss, wanting to get to the 4 week olds. So I shut everything up and let it out with the others. The four week old were lovely to the little one, but then the little one starts trying to pick in their eyes as they were resting in the nest box! I immediately put naughty chick back in the brooder. I was shocked, what kind of behaviour is that? I was all going so well until that happened.