How old are they all? What sex? Do you have any really dominant hens or aggression issues? This makes a bit of a difference. I will tell you what I did. Some swear by this technique and others say it doesn't work. I had 2 new hens to introduce to an established flock. No roosters. All about the same age. (1-2 years old.) I did the "sleep and Sneak". You wait until your hens are asleep for the night and then quietly slip the new hens onto the roost. (This is after having quarantined your new additions for several weeks to avoid introducing new diseases). In the morning the hens look at each other and think.. "well, I don't really remember you, but since we spent the night together, you must be OK." For me, it significantly reduced the "pecking order" time. Some mild issues but not bad at all.