A necropsy is an autopsy, basically opening the abdomen and chest to look at organs. There are many online links and videos to look at if you Google “chicken necropsy” if you want to learn how or water a necropsy by an amateur or a poultry professional. If you do a home necropsy, take a lot of pictures of the organs, especially the liver and others, and post them here for any help. Here is one that show the organs and labels them for identification: