I do think the yellow urates in the case of the other chicken seemed to be due to the vitamins she was receiving, since they are normal now. I looked at the pictures of the hen that died, and agree that it was most likely fatty liver disease. Diet and genetics can play a part in that. After seeing fatty liver during a necropsy on one of my own hens, I became more aware of keeping them on a balanced layer or all flock feed, and limiting any extras.
