If and when you think she is done sitting and you want to take the eggs, you can either coax her off the nest with food, or grab the chicks and move them to where you want the momma to follow. If she doesn't follow you on her own then just pick her up and mover her. She should stay with her chicks either penned up in the safety of the coop or the three of them can be out with the flock. I do it both ways. Some hens have the natural instinct to protect her chicks and others don't. The hens who don't protect their chicks very well are the ones that I separate from the flock until they get a few weeks older and can flee from others. You can provide the mother hen her normal feed even regardless of the chicks. She will eat what she wants and she will alert the chicks to eat the starter crumbles and any other treats you might give her.