you'll need to get her some fertile eggs or break her set. If you put her in a coop or cage with a wire floor where she can't keep her body fever to set she'll be ready to go back into the hen house in about 3 or 4 days.
Once she's eating well and not setting on the coop floor all the time her set is broken. If you don't break her set, she'll stay until she either has babes or starves to death.
If you can get some less than 2 day old chicks and slipped them under her at night, she'll raise them and you can always give them away when they are grown if you don't have room.
good luck

simpleme ---- Can I break her set by putting her in a large dog crate minus the sold plastic tray? I have one of those and I wouldn't have to buy anything. The broody chicken's comb is laying down and is a pale color. I really do believe you when you say that she may die if I don't do something.

yes, that is exactly what I use. Put it on a cement, gravel floor or someplace that is not comfy and she can't maintain her body heat. Once she's in there she'll begin to eat and drink and give her about 3 days and then put her on the roost at night...I'm always breaking them, I have about 20 that will set and I can never find homes for the babes and don't have room for them. Works for me all the time...

simpleme --- I would like to thank you very much for your advice on how to "break" a broody chicken. Your method worked perfectly!

that's what this forum is all about. And I'm very glad to have been helpful.....