thats correct..BUT to get Olive eggers(unlike green eggers) a cross back to Maran or other Dark dark brown eggers is need it.. so a cross of the darkest green egger of the F1 hens back to a Maran rooster is need it, and this cross will produce 50% Olive egger birds(50% of that number are females) so say you hatch 20 eggs. and 10 of them are females you would expect 5 of them to lay "Olive" eggs at this stage. but how can you tell wich of these single combed hens will carry the blue eggs? well there NO WAY to know, that is untill they start laying, so you would have to keep all the hens untill they start laying. and thats for females. for roosters? how can you know if they carry the blue egg gene? there is absolutly no way to tell them apart from the other single combed roosters... thats the Beauty of using the Pea combed EE hens that are known to lay green eggs. they will produce pea comb birds, males and females and as I said you have 95% chance the pea combed birds carry the blue egg gene, making culling easy and having to expend less money on feed for birds that wont lay Olive eggersI would hope that CCL also carry 2 copies of the blue egg gene.... then you would get 100% off spring with the blue egg gene.