I guess we aren't understanding what you are saying here. There's no way that she has had an egg stuck in her for 2-3 months. Do you mean she repeatedly becomes egg bound?
Are you meaning that she is an internal layer? Egg bound hens die within a few days at the most, but hens who begin to lay internally, dropping the eggs into their abdomen live much longer most of the time but it does kill them eventually.
There are implants that stop birds from laying, often used in parrots. Not cheap. You will need to find an avian vet and discuss.