How to introduce new chicks to adult chickens?

I had this problem, just posted about it the other day. I locked my babies up in a wire cage int he middle of the coop for a day and that didn't work, so I locked my bantam roo (the pecker) up and let the little ones loose. After a day I guess he got the picture and was much nicer to them. My dh is building me a new coop just for my bantams because of this, so I guess that will solve my problem. I think seperating them where they can still see each other gets them used to each other.

I can't give any advice about the dog attack.  I've had one chicken, a SLW, that survived a dog attack, and it didn't seem to change her personality.  I do have 5 RIR pullets who seem much more bullyish than the others, pecking at everyone every chance they get.  I don't know if that just goes with the breed or not.

I would wait to introduce the babies to her until they're feathered out and a little older.  She may kill them.  Some say to wait until they quit peeping, because even the difference in sound will cause the older birds to go after the younger ones.

This being said...  my experience has been pretty good with introducing younger birds to older ones.  I had 5 4-month-old pullets in the hen house, and 6 6-week-old polish chicks to introduce to them.  I have a wire dog kennel that I put the chicks in, inside the hen house, for them to all get used to each other.  For the first day or two, the big girls picked at the chicks through the cage every chance they got, so I moved the cage into a corner of the hen house so the babies could have a safe space.

After a couple of weeks in the wire cage, I sat out in the hen house for an hour or so each day for 2 or 3 days while the chicks were loose.  I have one particularly aggressive big girl who went after them a few times, but with my presence in there with them they were safe and got used to each other.  Probably about the 4th day, I let the polish chicks out, and tied the kennel door so it stayed open 2 or 3 inches - enough for the chicks to get in for safety and keep the big girls out.

My aggressive big girl is still the boss of the flock (her name is Queen Latifah ), and the smaller birds all steer clear of her, but there's always going to be a pecking order with chickens.  They all get along just fine now.  I repeated the process a couple weeks later and introduced 26 more chicks into the hen house, and all is as peaceful as a chicken coop can be!