It is hard at first, and I always dread to do one. But I have had chickens for over a decade, and I have lost most of my original flock. I have learned a lot about what has killed them by doing necropsies. There have been reproductive disorders, cancer, a case of fatty liver disease, ascites (water belly,) and other problems. There are many videos online to help with identifying organs. An d many post pictures here for advice. But it is understandable that it is best for you to just bury the hen.