Sorry that you lost her. What state are you in? Most state vets can perform a necropsy on Monday, but the body would need to be kept cold, not frozen and taken in Monday am. You may also do a home necropsy taking pictures of her organs, and noting any fluid inside the belly. I do them on hens I lose, and sometimes you can see evidence of common cancers, egg yolk peritonitis, and water belly. If you do one, take pictures of the liver, intestines. Here is one someone else did today and their hen seemed to have oviduct cancer:
https://www.backyardchickens.com/threads/nercropsy-help-please.1645279/
https://www.backyardchickens.com/threads/nercropsy-help-please.1645279/