How warm is it where you live? How big are your six week olds? Are your hens a lot bigger? What food are your hens eating?
Usually I wait at least the young one's are on grower, I switch over between8-9 weeks. That way, you can feed the whole flock grower and provide free-choice calcium (oyster shell, etc.) that the young one's won't be interested in but the older hens will eat as they need it.
You will need to keep them separated until the young ones are old enough to defend themselves(12 weeks or more). Otherwise, they will get pecked to death and killed. They are not old enough to defend themselves in the pecking order. I kept my chicks separated by a dog kennel. It took at least 3 weeks to integrate once both groups were the same size.
Soon I will be in your shoes, so here is my plan, hope it helps:
around 5 weeks they will be put in the coop with brooder box and heat lamp at night (its going to get chilly soon in New England). They will be seperated off to a small section of the coop with chicken wire and get their own access to the run. This way, all the girls can see eachother but not peck eachother and you can keep the food seperate. They will live this way until they are all about the same size before I integrate them. Some people on BYC have even suggested removing the wire at night and placing the new girls on the roost with the others. Theory being that when they wake up in the morning its like they were always there!
Just make sure that there is plenty of food, water and places to hide as the new girls are sure to be at the bottom of the pecking order!
Quote:I agree, good plan. The other way to put them together when they are finally big enough is in a large area like your back yard, so they all have places to escape to. If you try it this way, I'd suggest some sort of treat at the same time.
Looks like I am in the same place as the original poster. I have my 6 week old chicks (4 cochin mixes) in a 2 foot x 4 foot cage with a roost. I keep them in there all day, except for about 30 minutes when the other chickens are still in their coop/run. I worry that the babies don't have enough room in that small area. Are they ok in there until they get to 10 - 12 weeks old? Do they need a bigger area?