Her abdomen wasn’t filled with fluid but to me at least she seemed to have a lot of fat. Her gizzard looked healthy on the inside, again quite a bit of fat surrounding it.
I'm sorry about your hen. Good of you to share your photos.The biggest thing, which you’ll see in the pics is her liver. Definitely something wrong with it but idk what it means? Her heart also looked small to me but I’m no expert. Bile duct looked large too,
I agree, if possible, call your state lab and see if they can look at your photos.
I tend to lean toward Fatty Liver Hemorrhagic Syndrome (FLHS), could have been sudden onset, I don't see a typical tannish/pale liver, but who knows.
Another condition to consider would be Avian Leukosis. @azygous
There is quite a bit of fat in the abdominal cavity. Ovaries and Oviduct look normal to me. Heart is hard to say if it seems small, could be.