OH - forgot to say that after the hatch (which may go on for several days) and she is satisfied that all the eggs that are going to hatch have, she will want to leave that nest and take them somewhere else. They don't stay in their brooding nest after the hatch. Probably instinct to get out of there and find a safe place away from any rotting eggs, etc. left in the nest. Probably also a desire to find a place safe from predators.