If you are only noticing this change in cold weather, it is likely nothing to worry about. It is not uncommon for chickens to stop laying or to lay less as the weather cools. This can mean that eggs move through their system slower, and the roughness that you are experiencing is simply an excess of calcium getting layered onto the eggshell. This is not dangerous to the birds, and does not affect the quality of the egg. Our friends at the University of Florida Extension Service detail some of the causes of eggshell variation on this handy page:
If you are only noticing this change in cold weather, it is likely nothing to worry about. It is not uncommon for chickens to stop laying or to lay less as the weather cools. This can mean that eggs move through their system slower, and the roughness that you are experiencing is simply an excess of calcium getting layered onto the eggshell. This is not dangerous to the birds, and does not affect the quality of the egg. Our friends at the University of Florida Extension Service detail some of the causes of eggshell variation on this handy page: