I have 1 rooster and three rhoade island reds that i have had for about two years. they have not been broody at all, after doing a little research, I read that barred rocks are broodier hens . I bought four chicks about two months ago and they are almost the same size as my others. I have kept them separated. Chicks in garage in pen and the older girls and rooster in coop and pen outside. how should I go about introducing the new pullets to current flock?