Surrogate hen sitting on eggs due to hatch any day. Better to keep with hens or separate once hatche

[nippynik]

I have a Serama sitting on her bff, a Silkie's, 8 eggs. They live together with Mr. Silkie although he can be separated at any point. The eggs are almost ready to hatch and i'm planning on putting the chicks in their own heated pen once born. (I've raised day old chicks for several yrs without any problems.) Once the eggs have started hatching will they be safe with the adults? When should I separate them? Is it best off to even separate them? I'm a first time home breeder and just want the best for everybody! It's funny yesterday the hens were both sitting on the eggs although the Silkie hasn't been broody at all.