we have three barred rock hens. One is looking pretty rough right now, and her eggs are getting lighter and lighter. Today it was sort of speckled brown and white.
I have several (6) BR hens , 2 lay the lighter eggs 4 the darker ones. Some times I get the eggs that have speckles on them. I'm not sure of the cause of the difference, But mine are only about 11 months old. My father says that they are still pullet eggs and that this my have something to do with it. I don't know for sure though.