If you do have a broody, you will most likely want to move her away from your other hens while she is on the nest anyway, and certainly when the little ones hatch. Sometimes other hens are not so nice to babies.
Put together a 3-sided nest box they can get in and out of easily, and have the food and water close by so that mom doesn't have to go far in the last week or so of sitting. Even though chicks are surprisingly tough, a fall from 24 inches is not good if you can possibly avoid it.
I hatched my first babies under a hen in January and it was the most fun I've ever had with my chickens! Sooooo cute!