I am trying to introduce my 4 chickens together and have just found how scary it is. I have (2) 6 week olds and (2) 12 week olds. I have a small coop that will only hold max. 6 hens. So I dont have much room to do some of the ideas others have offered up. I would try to keep the 6 weeks old in the brooder longer but they are getting so BORED they needed to get outside and explore. I did not realize how stressful introduction is and I am terrified they will kill each other. The pecking on the back of the littles ones neck is normal? At what point does it become serious bullying? And at night if I put them in the roost togther does that not create a much more dangerous situation as the babies will not have anywhere to run.... AHHH need help!