I have two roosters; a Black Copper Marans and a Splash Marans. They are together with some BCM hens, 1 Splash Marans hen, and 4 Easter Egger hens. I recently hatched 1 dozen BCM eggs from a local breeder alongside 23 of my own eggs. Hers had a good fertility rate. However several of mine developed nothing at all. I ended up with 12 babies from my own eggs. And none of those were blue. A splash rooster mixed with a BCM should produce blue. Thats why I got him, I wanted some blue babies. Now, the Splash Marans is the dominant rooster, however I have seen them both mating with different hens. I do think each rooster is partial to a few certain hens. I am guessing that the infertile/undeveloped eggs are from hens only mated with the Splash rooster. They are all 2 years old, I have had them since they were babies. It has not been excessively hot. All in good physical condition. This is my first attempt hatching anything I will admit. But there was not even the start of a baby in so many eggs, that I dont think it was an incubator/newbie issue. I would be sad if my guy was shooting blanks. He is a nice rooster and handsome. Others thoughts?