I had a 13 weeks old Isa Brown die today. I noticed 3 days ago that she wasn't keeping up with our small flock, but lagging behind. I put her in a separate cage the same or next day and observed her. She ate less and less over this time until today which was mostly nothing. Her drinking also became less. Her poops were normal at first, but became mostly white liquid with little or no solids. She was losing weight and becoming very boney. Her comb was somewhat purple and laying down. Her legs felt cool. She closed her eyes frequently and her breathing became more and more labored. I tried feeling her crop, but am not really sure where it is yet. I'm thinking it was empty. When she died she was flipping all over and a yellow liquid came out of her mouth. I'm not sure how much, but probably several teaspoons worth. She never had a nasal discharge prior to this. Can you guess what made Harmony die? I'm concerned for the rest of my girls.