Yes, I know there are many threads about this - I've been reading through them for some hours! Our current set up: One coop about 120 square feet. "Up front" the original set of 4 hens, about a year old. Introduced to them last month, the set of 4 (plus mama) "New Years" hatched hens - now almost 6 months. This is now the "crew" - 9 hens all together, no roo. To mix this bunch wasn't too difficult - the newer hens moved to the front of the coop first, then took the eldest, original hens from their old coop and put them all in at night together in the front half of the coop. Both of these groups had seen eachother free range for a few weeks first, then spent about a week prior to moving free ranging all together. In all, very smooth transition, minimal pecking and all is well. Now: We have 20 chicks in the "back" half of the coop - ranging in age from 7-2 weeks. The babies and grown hens can all easily see eachother since the only thing dividing them is an 8 foot wall of chickenwire in the middle of the coop. Our cornish x (7 weeks old) are also in the mix, they sleep in a tractor on the side of the hill where the grown hens all freerange, and as of two weeks ago they have been freeranging on the same hill together. A very small bit of pecking but the original flock doesnt bother them much and the cornish cant make the ramp to the coop so not home territory squabbles. I dont have a "run" to put the newbies in but could fence them a small area inside huge fenced hill so they can get outside (the hens have a fenced half acre or so to free range on). However, to exit the coop they must go out the front where the big hens are - meaning taking down the chickens wire - the "human" door is the only way into the back and it is not inside the fence. Havent dared to try this yet. How long should I wait to introduce the 20 babies - should they be lots bigger? Or would it be better to mix them now while the distracting cornish are still plundering about the hillside (only until end of June)?