Oh, *boy*. We felt that title in our bones. The optimism. The careful planning. The separate cage, the supervised introduction, the quiet hope that maybe, just *maybe*, this time the pecking order would be a polite discussion rather than a full-blown fowl riot. And then reality swooped in with a vengeance. Hardcore pecking. Cornering. The kind of bullying that makes you want to grab your new Bielefelder and Pekin bantam and start a sanctuary in the living room. We've been there. We *are* there. And we have thoughts.
First, let's address the bad advice you were given. Whoever told you that tossing young birds into an established flock is a non-event has clearly never watched a chicken hold a grudge. Chickens are basically tiny, feathered mafia members. They have a hierarchy, they enforce it with zeal, and they do *not* appreciate newcomers showing up and acting like they own the place. The fact that your four older Sussex chickens, already a bonded unit of seven weeks, went full sentinel mode on the new girls isn't surprising. It's actually textbook. But knowing it's normal doesn't make watching it any less distressing. You're not overreacting. You're paying attention. That's the first step to not ending up with a traumatized flock and a broken heart.
The nighttime introduction trick is a classic, and it has merit, but only if you do it right. The logic is that if everyone wakes up together in the dark, they might just accept the newbies as part of the furniture before the sun comes up and the pecking order debates begin. But here's the catch: you need to make sure the new girls aren't going to get cornered in the coop before morning. A dark coop can be a dangerous place if one chicken decides to hold a grudge in the dark. We'd suggest you move the cage *inside* the coop for a few nights first. Let them sleep side-by-side, separated by wire, so everyone gets used to the sound and smell of each other in the actual sleeping quarters. Then, after three or four peaceful nights, do the midnight swap. Slip the new girls onto the roost while everyone else is asleep. Be prepared to intervene at first light. Keep a spray bottle of water handy, a quick squirt at the bully breaks up a fight without traumatizing anyone. And for the love of all things cluck-tastic, do not leave them alone until you're sure the peace is holding.
What this means for you, practically, is that you have a solid two-to-three-week integration project ahead. It's not a crisis. It's a process. Your attachment to all six birds is a good thing, it means you'll be patient, observant, and willing to adjust. If the nighttime trick doesn't work after a week, go back to the cage-in-coop method for another week. There's no shame in a slow integration. The worst thing you can do is rush it and end up with a hen that's too scared to eat or drink. So here's our concrete take: keep the separate cage in the coop for at least three more nights, then try the midnight swap. Watch them like a hawk for the first hour of daylight. If the older four still act like territorial gremlins, separate them again and try the whole thing over in another three days. Your flock will figure it out. And if they don't? You'll have a very interesting story to tell at the next chicken-owner meetup.