I have a small flock of 9 hens that are 43 weeks old. All of the girl have been good egg layers even in this cold Michigan weather. I have one Buff Orp that has started to lay eggs with well "marbled" groves throughout the shell - almost through the shell. These eggs have not been dropped nor cracked. I've seen a few of those since September. Any ideas? I've been searching BYC and the Internet for help but I can't find anything that addresses this problem. Thanks. I gathered the following 8 eggs tonight. See the bottom right egg. Here is a close-up. There are cracks on all sides.