I have been up for the last couple of hours with a chick that had been fine when checked on them, running around eating drinking. Then I heard a loud cheep and checked again. It was down on belly gasping opening mouth to breathe audible clicking noise from chick with each breath. It went down hill fast, died within 1 1/2 hours. It became very pale on legs and face nearly white and became cold. The clicking became louder and audible from 3 feet away. It flipped over on its back cheeped very loud and died. I did a necropsy and found blood pooled around the heart. It died from some type of heart failure. All other organs were pale as if all blood was around heart. No signs of cocci in intestine, no blood in the tract. Sad this happened but at least it was a happy nugget the 3 days it was with us.