We have ten chickens that lay between five and ten eggs a day. Last week we found an egg that had a paper like consistancy. The shell was not hard like the rest and was broken. Then yesterday we found another one. This time the shell was formed but was again paper fine and soft. Can you tell me if the chicken is sick or if this is common. They are fed oyster shell grit, layer pellets and cracked corn and whatever they find in the yard since they are free range. I have no idea which chicken is laying the egg or even if it is the same one. Thank you so much for your help.