Look up egg binding, soak in warm water is usually the first thing suggested....
.....and I will ask to have this thread moved to the emergencies forum.
Adding some info about what you are feeding would be helpful, as could your climate/location.
Is she pooping OK?
Does her vent look normal?
Have you tried gently inserting a lubed, gloved finger up to feel egg?
Lack of calcium can reduce the contractions needed to move an egg along and out.
Might want to do a search on egg binding and see if you can find a clue to what's what.