Faded egg with dark round circle

[bosstwins]

Today I found an egg that looks as if it it has been sitting in the sun and faded, however we had just cleaned out the coop a few hours earlier so I know that this egg wasn't there at the time. The egg looks faded with a dark circle on it. I've found these a few other times and threw them out thinking that it had been laying around and was no good. Our chickens always lay in the nests except for these few odd eggs, we find these laying outside or on the floor in the coop. Any ideas whats going on? We just have a small 6 chicken flock and only 2 lay light brown eggs, but I'm not sure which one is doing this. None of them are acting odd and this is only the 3rd time I've seen one like this.

 

[Choco Maran]

That is normal. It is just a color problem on the shell it's self. There is nothing wrong with the egg. When the hen is putting color on the egg on part just got more than the rest.