Sorry for your loss. If you still have her body, wrap it in 2 clean garbage bags, then refrigerate it or pace it inna cooler on ice, but don’t freeze it. Then you cannget a necropsy through your state vet lab. They can give you a diagnosis with a necropsy. Here is a list of state vets to contact:
https://www.metzerfarms.com/poultry...L5h4Xt137GBu32pWJZSRUY5DYhQyVrd4ODmF-Ab8otocc
https://www.metzerfarms.com/poultry...L5h4Xt137GBu32pWJZSRUY5DYhQyVrd4ODmF-Ab8otocc