How do I know when it's time

So this is my first time with letting the hens raise the chicks. But it just occurred to me I don't know when it's time to get mom out or will she decide that herself?
All my hens are banty cochin x's raising lrg x meat chicks with some layer replacements. I worry that I will overload them. I mean so far everyone is doing well but you get looking around and planning your next step. And pretty soon I've over thought it lol

The hen will decide herself! She will get tired of the chicks and start ignoring them around 5 to 6 weeks old. She may even get annoyed and give them a peck or so if they bother her too much at that stage.

Thanks bob. I kinda figured so but thought I better check with the pros

I second that notion, Mamma hen will make the decision herself and will let her young know when it's time to fend for themselves. Like Farmer Bob mentioned, somewhere around 4-6 weeks she will begin to stop mothering them.