Integrating new chickens into flock

[Strathmorechickens]

Hi there, I am curious on everyone’s thought on how to integrate new chickens to the flock. I have 4 Brahma Hens that are about 21ish weeks old. I have 8 new Brahmas that are about 9 weeks old. The new chicks are currently housed in the coop which I want them all to be in for winter. I had the older hens in the yard free ranging and then we brought the 9 weekers out to meet the big ones and the big ones looked like they were teaming up and “attacking” the new ones. I then moved the older ones into a fenced run and let them be near each other for half hour with a fence in between.
Any recommendations on how to make the integration go smoothly and how to go about moving the older ones into the coop with the young? Thanks!

 

[CluckerFamily]

I do a 2-3 week see but no touch integration. And then they mingle under supervision, if every thing goes well... great, if something goes wrong.... 1 more week of see but no touch seems to do the trick.

 

[aart]

Integration Basics:

It's all about territory and resources(space/food/water).
Existing birds will almost always attack new ones to defend their resources.
Understanding chicken behaviors is essential to integrating new birds into your flock.

Confine new birds within sight but physically segregated from older/existing birds for several weeks, so they can see and get used to each other but not physically interact.

In adjacent runs, spread scratch grains along the dividing mesh, best if mesh is just big enough for birds to stick their head thru, so they get used to eating together.

The more space, the better. Birds will peck to establish dominance, the pecked bird needs space to get away. As long as there's no copious blood drawn and/or new bird is not trapped/pinned down and beaten unmercilessly, let them work it out. Every time you interfere or remove new birds, they'll have to start the pecking order thing all over again.

Multiple feed/water stations. Dominance issues are most often carried out over sustenance, more stations lessens the frequency of that issue.

Places for the new birds to hide 'out of line of sight'(but not a dead end trap) and/or up and away from any bully birds. Roosts, pallets or boards leaned up against walls or up on concrete blocks, old chairs tables, branches, logs, stumps out in the run can really help. Lots of diversion and places to 'hide' instead of bare wide open run.
Good ideas for hiding places:
https://www.backyardchickens.com/threads/a-cluttered-run.1323792/