Most likely the hens will kill the chicks if you put them together. I'd keep them apart until the chicks are big enough to defend themselves. Normally the mother hen protects them from other hens.

I'm assuming you are buying a group fo 18 day old chicks--I would agree with the most recent post. The more mature birds will not feel maternal, unless the chicks come from their own personally hatched clutch.

We integrated multi-age groups into a single flock twice now--I know some folks recommend get them all together the earlier the better but that has *never* been our experience. The first time we tried it the older hens ran a pullet into the fence on a rainy day--we were at work all day, and when we got back we found a cold, wet pullet, who nearly died from infections coryza.

The second time, was not quite so bad--but we noticed the older hens would keep the youngers from food and even water. Since that's so critical early on, we decided better to separate them until the youngers were big enough to defend themselves.

We've found it works better to keep the chickies indoors with us as long as possible, and have used some rather large wooden crates to pull this off (like a 3' X 5' X 3'). Then we usually build an extension on to the coop, keeping the two flocks completely separate at first, with separate runs as well. Then over a period of months we move them closer and closer together, with it working best to fully integrate about the times the younger group is nearing full size (so about 5-6 months or so). Then they can hold their own getting water and food.

The little chicks won't have a fully developed enough immune system to be able to be around the hens for at least a little bit.

If you have to keep your chicks in the coop, I recommend using chicken wire to fence off a portion for the babies, something your big girls can't leap over. Also, your coop will have to be much tidier than usual, or your chicks will be more likely to suffer from exposure to adult tolerated levels of coccidia. If you must keep them all in one dwelling, hate to say it but I recommend a feed with a coccidostat, or meticulous monitoring of their water with trace quantities of apple cider vinegar added, and regular mash of crumble feed with yogurt.

For more info check out

www.angelfire.com/falcon/th...links.html

happyhens.blogspot.com/