I have some new hens that have recently started laying. A couple times now I have found an egg that is a chalky white color. Otherwise normal egg. This morning one had a little poo on it so I rinsed it off and it was a deep brown color. as soon as it dried it turned back to the chalky white color. Any idea why this may be happening? I think it is one of my SLW that may be laying this eggg but Im not sure.