Lately I have one chicken (one year old prod red) who is having shell making problems. She has had several thin shells and a couple of wrinkled shells, like the one pictured below. I am not going to cull her because of this but would like to know if this is genetic or is there something I can do. All the other hens lay nice thick shelled eggs. She gets plenty of calcium.
![61549_odd_egg.jpg](https://www.backyardchickens.com/forum/uploads/61549_odd_egg.jpg)