I had a huge egg today - a double yolkier - one of the yolks was fine, the other was runny. My hens are a little over 2 years old. I still haven't found anything to explain it. It's not the same chicken all the time - different colored eggs. They all get the same food.
Weird.
Reviving this thread because I would love an answer. Does anyone know why this happens? I collect eggs every day - usually a couple of times a day, and once in awhile when I break one, it comes out runny.