I am sorry for your loss. Most state vets will do a necropsy on a hen if you send them to the lab or ship overnight. Of course they are usually open only M-F and this upcoming holiday week might be complicated. It is not good to massage a soft crop and put their head down to vomit, since they can aspirate if food comes up into the throat. It sounds like she was very sick. If you could do a home necropsy and post a few pictures of her organs, that might help us see if anything looks unusual. Here is the list of state vet labs to contact early Monday if you want a vet necropsy: https://www.metzerfarms.com/poultry...BzutBaxDW7n0XgGRPg9jhCT--nGWzfpoumNLEtrKyzyRV
If you would like to attempt a brief home necropsy to take some pictures of her liver, intestines, gizzard, oviduct, it might help. I understand if you don’t or have buried her already. Here is a video of a vet necropsy with the organs labeled: