The other morning I went out to take care of my chickens and noticed that one of my Nankin hens was in the nest and just didn't look normal. I had to get to work, so at lunchtime I checked on her again and she was still in the nest and her comb was kinda bluish. I picked her up and checked to see if she was eggbound (I had a hen act like that one time that was). Anyway, that wasn't the problem so I checked her over. Didn't see anything out of the ordinary, her crop was full, and when I put her down she drank water. She stayed basically the same all afternoon and the next morning I found her dead on the ground at the back of the pen. Does anyone know what this sounds like? I hope it's nothing contagious because I have other chickens in that pen and pens surrounding hers (my new chicks are in the pen right next to hers

) She wasn't really old...about 3 years old so I don't think age was a factor.