Use golf balls instead of eggs. When she starts to sit on the golf balls, she's ready for you to give her eggs.
Make a home for her away from the others (use a dog crate, a rabbit cage, or something like that) so she can have some privacy. Make a nest (I cut a small cardboard box and use that with shavings) and put food and water in the new house.
Remove her from her golf ball nest at night while they are sleeping. It will be less stressful for her that way. Put her in the new nest with the eggs. She will arrange the eggs and push them under herself.
She will appreciate the privacy, trust me! The last thing she wants is for other hens to bother her or try to take her eggs. Putting her by herself insures that she will get up to eat and drink because she doesn't have to worry about the "dangers" of other chickens around.
My broody is in the house right now. I put a towel over her cage so she feels hidden. She gets upset when I take the towel off.