I would take her off the nest and offer her feed, water and a walk around. If she gets off the nest, her natural inclination should be to relieve herself. Some broodies just won't get off the nest by themselves, though most do-just when no one is looking.
Another suggestion is to make sure she's in a place that is private so she will feel comfortable enough to get up and poop/eat/drink. She may be so worried about the activity around her that she just sits and watches her eggs.
What works for me is bringing them in the house and putting them someplace where they can "hide"... in a spare bedroom or in the corner of the office. I keep them in a huge tupperware storage container and put a towel over one side so she can sit on her eggs in private.
I'll never see her come off her eggs, but I'll know that she has because there will be poop and eaten food/water.
She is in a large dog kennal with attached pen with food and water. She is stuck on the egg. I don't know when the egg was first sat upon is it possible they are due to hatch soon so she wont get off the nest? I put the egg to my ear and couldn't hear anything but when candling it look pretty well form but I couldn't see any movement.
i agree with rooster, mine will hold it, sometimes for a day or two, sometimes more, then she will get off the nest and lay a turkey size broody pellet.. huge...