An apparently healthy hen dropped dead overnight so I decided to open her up. All looked normal until I got further up the body cavity and found a rock hard mass the approximate size and shape of an egg. It had a shiny whitish blue membrane over it but once cut opened was deep red in color. Inside it was solidly packed with mud, wheat grains, oyster shell and a few tiny flecks of grass. I jumped to the conclusion that she died of an impacted crop but I just found pictures of her the day before she died looking perfectly healthy. Am I missing something here?