Help! Hen sitting on bad egg, what to do??

[Maqui25]

Hi, so there's a hen who started laying under the porch in a hard to reach place. I used a long stick to take out the eggs, but she became broody after laying the last one. She's been sitting there over a single egg for over 30 days by now so it probably went bad. I'm afraid she's gonna get weak and sick sitting for so long, but also I don't know if it's bad to be broody and come out with no chicks at all. We can't move her or remove the egg, so what's the best course of action? Leave her alone until she gives up? Wait for her to move and take out that egg? (but I've never seen her out all these days) or give her eggs from another hen so she can sit on those?