Broody now hatching in shared coop

[MummaZette]

I have 18, 1 & 2 yr old pullets/hens
along with 10 5 wk old straight run chicks
our Black Star Mumma just hatched her 1 chick from a clutch of fertilized eggs I bought 3 wks ago.... She has been confined in a space under the nesting boxes all this time separated/protected from the others.
Now what? I want her to do "her thing"

• do I need to continue to keep them all separated from the rest of the coop and if so,

1. how does that allow Mumma access to get up herself finally in a few days and go out into the sunshine again?

• Now that she's ready to eat again, do I feed her layer pellets? cause she's gonna have access to the mash and I do get the medicated feed. What harm/concerns do I need to know with her and actually now the others having access to medicated feed??

I can't located my Raising Chickens for Dummies book and know this is the next best place to go for guidance.

Thanks in advance!