Introducing new chicks into the coop?

[FloridaHen]

I have a group of chicks I bought from TS first week of March and a new batch I just bought last week. I would like to know how soon I can mix the 2 groups? The 2 Cornish Crosses (a roo and a hen) are going to a new Home soon as they were not what I wanted due to their major size and the fact I didnt want a roo, also I am giving the new owner the Hen so he can have a mated pair,and a mistake on TS's part when they got mixed in with Bantam pullets.
After that, I am left with 3 leghorn girls aka "the angels" (Lena,Lita and Lucia)...lol. When can I add in the 6 new ones, 3 GSL's, a polish tophat, a possible cochin or silkie bantam, and a mystery bantam. The newer chicks are about 2 weeks old maybe?
I don't want the other 3 to get big heads over having a coop to themselves.

Brynda
Head Hen of the Beaks and Talons Inn aka the coop

 

[BayBay Peepers]

You'll want to wait until they're of like size. You're newer ones are still going to need heat anyways so you'll at least have to wait until they're fully feathered. If you don't want to wait as long as it would take for them all to reach a like size I would suggest a night time add. And make sure to check them right away in the morning to make sure all went smoothly.

 

[azygous]

The very best thing you can do in order to achieve your objective is to raise them all together while providing enough separation to insure the 2-week olds aren't abused by the older chicks.

I would move the entire lot into the coop after providing a partition to separate them, a heat lamp in a corner of the section with the younger chicks, food and water in each section.

After a couple of weeks, you can begin letting the chicks mingle and see what happens. chances are good they will get along with no problem after getting accustomed to each other.

You want them to treat one another as being from the same unit, and the only way that will happen is if they are raised together. If you raise them separately, out of sight of each other, two groups will form and each will consider the other as outsiders, presenting possibilities for friction.