I'm sorry your hen is not well. Unfortunately it does sound like a reproductive problem. It's not uncommon in hens over the age of two. It could be internal laying, salpingitis, cancer, all are not uncommon. EYP is often a symptom of one of the other underlying conditions. It may be infectious matter building in her abdomen, or fluid that builds up due to too much strain on the liver, or organ failure. The prognosis for hens with reproductive problems is usually poor, there are not many options for treatment, and it will usually only help temporarily with symptoms. I usually leave mine with the flock until they are no longer doing normal chicken things, isolating themselves, not eating or drinking, obviously not feeling well. At that point I euthanize. It is often difficult to know exactly what is going on until a necropsy is done, many reproductive problems will present with similar symptoms. I'm so sorry that the outlook is not better.