I was mowing today and was heading toward the coop and noticed one of my RIR's laying near the edge of the chicken run. I've had all 4 of them for a year and a half now, they all seem happy and I average about 3 eggs a day. Nothing seemed different over the past few days. The dead chicken had no signs of blood and I don't think she had been laying there long. I did notice one of the eggs today caved in at my touch it was so soft, I keep crushed oyster shells in a dish for them at all times. One of the chickens will leap from time to time and land on the other chickens, is there a possibility that she jumped from the 5' high perch and landed on the other chicken possibly breaking its neck? I also looked at the chickens hind quarters and didn't notice any egg stuck or anything (egg bound?) There are also no signs of anything getting into the coop from the outside. I'm not sure what happened, any ideas? This is my first group of chickens I've ever had so its still new to me.