One of my hens died

[nuthatched]

Or a heart attack, I'm sorry for your loss.

 

[Eggcessive]

Very sorry for your loss. You could try to do a home necropsy to look at her organs, taking pictures to post here for opinions. Or you could keep the body refrigerated until Monday and have your state vet perform a professional necropsy. If it was fatty liver disease, you may see a large blood clot, a lot of fat, and a tan or putty colored liver. Here is a list of stat vets to contact if you go that way:
https://www.metzerfarms.com/poultry-labs.html