This thread is very interesting. I have two chicken coops one with a banty rooster and one with no rooster. when I read about the bullseye to tell if they are fertile I just had to crack open every egg had. I had the same thing happen!! I went out and looked over the ladies real good to see if by some chance there was a rooster hiding!! I found nothing soo I am intrigued by this. I suppose the duck mating with a hen is not that crazy. They are poultry so they are in the same class I suppose if it is meant to be it will happen. You could be the first and watch the people go wild for Chucks!!!!