I am getting ready to start integrating my old and new flock. Each year when this come there is a certain amount of dread because integration is never uneventful. The big chickens can be just plain nasty. There are two elements that cause all the problems.
Chickens don’t like newbies in their flock. Add new chickens to a flock and this upsets the pecking order of the flock. When a pecking order is not set, then everyone wants to peck on others helping to ensure they end up as high as possible in the new flock order.
Chickens like to pick on smaller chickens or chickens that physically look different. When integrating a flock like this you have bigs and littles. This year I have one white one who sticks out like a target.
One of the things that I do just prior to integrating my flock is put my new flock in an dog exercise pen. This allows the bigs and littles to start seeing each other and working more like a single flock. Often times the bigs will stand around the edge of the ex-pen waiting for the littles to get close enough to peck. This gives my littles a safe place to learn that yes, bad things can happen, and if you are going to be around the bigs one must be quick. We are in that phase. Next step is to open the doors on the ex-pen.