Should all Cuckoo Marans be expected to lay the signature dark eggs or is it just a percentage of them? You know, like the way blue coloring or frizzled feathers show up in only a percentage of certain breeds. I ask because none of the few Cuckoo Marans in my experience have laid anything but pale tan eggs. I had 2 I bought at the feed store and sold at POL at the county fair. They each had a cage-mate so I couldn't be certain the pale eggs were coming from them, but I never saw a dark egg come from either of them. One did lay a speckled egg one day. Then someone else gave me 4 Cuckoo Marans pullets she ordered from Ideal and again, only pale tan eggs, nothing darker. What could be the explanation?