When I introduce new birds to my flock (after quarentien) I taken them inside the pen in a wire cage with the flock roaming the pen, set the cage down and sit down and let them get to know each other that way for at least 20 minutes.
Then I let the new birds out to mingle while I stay in the pen to supervise.
I've had no problems this way, the pecking order gets straightened out quickly and with very litle pecking.