I found it best at night...they are relaxed and going to bed and so you usually won't see any scuffels then. I put them on the roost with the others but put them on the other end away from the others. Anyway, when they get up in the morning everyone will go about their usual business and you will probably see a little pecking, which is normal. The older ones need to let them know what the pecking order is and that will last a week or so. Keep an eye on them to make sure no one is being hurt...in other words, make sure there is no blood shed. They should do fine. Also, let them out to free range together. This helps give everyone space. Good luck and let us know how it goes.
If you want to add them during the day, I would do it in a "free range" situation, but frankly, I found that it's better if everyone knows where their "home" is first, so that's why I add them at night by putting them on the roost with the others. This is what worked best for me.
