About 10 minutes before we were ready to leave for Memorial Day weekend, I asked for someone to check to make sure the chickens had full waterers. Two minutes later my 10-yr-old daughter comes flying into the house screaming that something killed Miracle. (Miracle was a neighborhood stray Barred Rock that we rescued during the snowstorms in February. No idea where she came from, she was a juvenile, but we had successfully managed to integrate her into our flock of 4 and she had just been laying for about a month.) Went down to the coop and, sure enough, she had prolapsed and was lying dead in the corner of the run. Pretty gruesome sight if you haven't seen a prolapsed bird. Other hens were freaked out and huddled down in the other corner. Miracle, who obviously didn't live up to her name, must have been eggbound. Didn't have a whole lot of time to examine her -- hastily dug a hole and headed out for our vacation after calling to inform the neighbor who was hen-sitting for the weekend. Unfortunately, she had appeared perfectly fine earlier in the day. Possibly the only sign I might have had was that she was panting, but then again temps were in the 90's (after being in the 50's the week before) and all the hens were panting. Came running when I called and threw scratch. She did manage to get the egg out -- I found it in the nest box just a little bloody, but must have prolapsed in doing so. I've found a lot of information on what to do, how to identify an eggbound hen, etc., but nothing on the fundamental cause. (Yes, I know the egg is stuck, buy WHY?) Is this something that is hereditary or possibly due to a genetic malfunction? Are some breed more prone than others? Miracle always had problems -- laid smaller than normal eggs, shell-less egg once, fart egg once, sometimes pretty thin shelled or otherwise odd in appearance. The egg that did her in was not overly large, maybe a little rounder than normal, but would have been easily laid by any of the other four hens. She always walked weird in comparison to the other hens -- legs far apart and thrown outward as she ran. Maybe she had some sort of genetic deformity? Could it be diet? Miracle was extra large (heavy 7 lbs. compared to my other 4-5 lb. hens) and real feed hog. Probably due to her several weeks of wandering the neighborhood fending for herself in January/February. She always walked weird in comparison to the other hens -- legs far apart and thrown outward as she ran.