Not for the first time, I found a whole egg that was completely shell-less in the coop. it was on the poop shield, so was laid overnight. Another time I found one on the ground outside the gate. Never in the nest boxes, although I suspect if any are laid in the box they are easily broken; we have had eggs with dried yolk on them. any idea what causes this? my hens are 3 years old. It appears my Black Sex-link is the culprit.