I currently have my first broody hen and I'm super excited,

So first question :
She is still in the coop with my other chickens, only one rooster and one other hen. Is it safe to leave her in there to raise the chicks with the other two adults? Or better to move her so she is by herself with the chicks?
If it's best to separate her, when should I do that? After the chicks hatch or before? I am scared of disturbing her and something going wrong with the incubation/hatching.
Second Question:
I've got 9 seven week old chicks living in my other coop/run, right next to the adults. If I do have to seperate momma and babies, would it be ok to add 7-8 week old chicks in with two adult chickens? Hubby might have a meltdown if I tell him we have to build a third coop! lol.

And Third:
How do you handle feeding when you've got young chicks with adults? So far I've only bought day olds and raised the chicks, so feeding was simple, I did chick starter and then grower until they were ready to lay and then got them on layer and have fed that ever since. When you have chicks with mom do you just put layer and chick starter in the pen? If I introduce my teenagers to the adults do I just let them eat layer right away? They are still on chick starter.
Thank you in advance!! I really want this to go well so any advice or tips are appreciated!!
