There is a chance that a broody sitting on a nest that is typically used as a laying nest will be bullied or pushed out of the nest by the other hens as they attempt to lay their eggs. It is best to move the broody to another area in order to ensure she will remain undisturbed as the other chickens go about their business.
You have a few options. Isolate her from the other chickens in the coop using chicken wire and make her a little corner that is all her own, complete with easy-to-access water, food and a small area to get up and stretch for a few moments. You can put her in the other coop that you used for the chicks. Avoid giving the other chickens access with the wire tunnel as I mentioned before, they may bully her and break the eggs. Give her peace and quiet, so she can concentrate on hatching her babies rather than fending off curious or homicidal chickens.
When you move a broody, DO IT AT NIGHT. This will be less traumatic to her and make her less likely to abandon the nest and return to the previous spot. Once you move her, a good broody should settle right in for the duration.
Again, make sure you have food nearby (you can switch her to starter feed, since she won't be laying eggs and won't need the calcium - plus the chicks can immediately start eating it when they're ready with no worry of excess calcium to hurt their tiny chick kidneys). Offer her water and make the confinement area large enough for her to relieve herself away from the nest and stretch. She will only be off the nest for a few minutes at a time. Keep her area CLEAN! Broody poop is FOUL business and very messy. She will save all her poop for one big go to avoid leaving the nest too often.
I have also heard that you can line her nest with rose petals and herbs (like rosemary and cilantro) to keep her entertained and for a little extra nutrition during her brood. Meal worms are also an excellent treat to keep her from getting malnourished.
Lastly, keep an eye on her. If she abandons the nest mid-sit, you can lose the viable embryos. Some first-time mothers will do this... It's unfortunate, but it does happen... Make sure you are set up with an incubator (you can make one out of a Styrofoam cooler in a pinch - see the Brooder section of BYC for more on that) in case you have to grab the eggs and become a surrogate mama hen.
I hope that helps!
Good luck!!!
-MrsB
