Is 15 wks old enough to intergrate?

[sab]

Have 2 15 week old chicks and 3 year old + birds. The older birds have been 3 days/nights in their new coop & run. I'm thinking of bringing the 2 young ones in after dark and putting them on the roost below the older girls. They have free-ranged together and the most aggressive is the pekin duck that thinks she's one of the 3 chicken flock. She was raised with them. She charges like a tank at the young birds but as soon as I call her down she stops. I don't know what she would do to one of them. Do you think the 'chicks' are ready? They quit peeping about 2 weeks ago. That was cute - peeping one day and clucking the next. They know how to skittle out of the way. But they will be in the run this time and not open ground.

15 weeks??? Good? Or wait???

Thanks