Oh. I'm having the same issues. I keep reading and researching but the bottom line seems to be "it could work" which I have translated to mean that you could have big crazy drama or you could have small scale drama. I am hoping for small scale drama, the kind without bloodshed.
Here is the method I plan to use. Can't vouch for it because it's still in progress.
I have 4 barred rocks who are close to 6 weeks old and a batch of chicks who range from 5 to 3 weeks old. I have tried to mix them before and the rocks always go after the 3 week old EEs and peck them violently on the head. They scream loudly and run around in distress. It freaks me out. Maybe I just have to become a tougher chicken lady but I am not there yet. I have been taking them out when it's nice and putting them in separate puppy runs that are closer and closer together. Now they can see other but there is cage between them.
Today I put the puppy runs up against other in an L shape so at one point they are touching but the babies can always run to the far end to be away from the big girls if they peck at them or yell at them through the cage...which they do. Their hen house is built and the run will be finished soon. When the big run is finished, I am going to let the babies out in the main run and keep the big girls in their puppy cage in side the run for a few days to see what happens. I'll let them out when I am watching and if anyone gets too aggressive, she goes back in the cage. It could be only one of two of the big girls who get too rowdy so I am hoping to rearrange their status a bit.
No idea if this will work. If anyone has suggestions on improving my plan, let me know. I am desperate to get these chickens integrated so I can put them in their hen house. I want them out of my bathroom. They live in the bathroom in two separate tubs that are too small for them and they are quite unhappy about it. None of us are happy about it. I am concerned about letting the big girls live in the hen house before the babies are ready because they might get territorial about it and make it harder to mix them.
What do you all think?