when can I move

One of my biggest and older hens started sitting on eggs here a while back, I didn't have a roo in with them at the time, so I marked the eggs and started putting other fertile eggs under her and removed the ones that were not fertile. This morning I have one baby chick!
When should I move her into a private box, and out of genral population.A covered barn. The boxes are about 4' off the ground. If I move her eggs to a new box, will she continue to sit? All the eggs are not going to hatch at the same time, as they were layed on different days. I'm proud of my red hen and black and white fuzz ball.