Egg yolk peritonitis, anyone?

[CinnamonQueen12]

My chicken just passed away from egg yolk peritonitis. I was wondering about it. What causes it. After hours of research, I can't find out what causes it. Does anyone know?

 

[EweSheep]

Usually genetics if it is from hatchery stock. Or an impacted egg stuck up in the tract somewhere that it would calcified, making it miserable for the hen or fatty tissues.