Some of the others made a good point about your set-up. Size and space is what will help the newcomers be accepted. If you have a small set-up with limited space, I doubt you'll be very successful and I've heard bad stories of people who have tried. I have a good size coop and a really big yard (nearly 2 acres, although they don't roam that far). I've had good success over the years adding new hens. The greatest success I've had is havinga broody hen raise chicks. The chicks become readily accepted (for the most part) because the mama hen makes it so.