Haven’t ever brought new chickens to an existing flock? Well, this can be an experience you won’t forget any time soon. Best to understand the pecking order now before you learn the hard way. Here’s the truth, expect the worst, because your precious little newcomers are most likely going to be pecked hard by the older chickens. Your existing flock isn’t going to take kindly to the new birds presence around food and water, the nesting area, or the coop for that matter. Seniority among a flock is serious business and the reorganization of social ranking can be brutal, even deadly. Space, space, and more space for a flock is a definite plus when introducing new birds. Multiple feeding areas and ample housing is equally important. Remember, size matters in the chicken world, the smaller weaker birds are at the greatest risk for injury and the least likely to get access to food.
Introducing new birds to a flock is not easy, even if the new birds have been housed directly in their view. My suggestion to you is to avoid this unpleasant introduction altogether by setting up separate housing. If this isn’t possible because you’re limited by space, I found a good resource from BYC about Methods of Introduction to help you and your birds make this difficult transition.