Hen on 23 eggs!

[LaceyM]

Im still in my first year with chickens.
We thought we lost a hen. But she showed up one day. I followed her to under the front porch. She has a HUGE nest! 23 eggs. We candled 2 eggs and we are guessing they will be hatching any day.
I have decided to not let her raise them.
My questions:
Out of 23 eggs... how many should i expect to hatch?
When should i remove the chicks from the mom?

Thank you.

 

[AMoffat123]

Candle all of them first, which will give you a rough idea of how many that are going to hatch.

 

[LaceyM]

I think today is day 20. Since she went "missing" is it ok to check them this close to hatching?