I have a silver hen that is 2 yrs old and has had chicks and is proven. I have two cockerels 7 months old and 8 months old. The younger one was with this hen and I had clear eggs. Therefore, I used my older rooster who has fertilized eggs with two different hens on my silver hen. However, I started getting clear eggs from him as well. I saw them try to mount her and seems successful, however, I am disappointed with clear eggs. She does it mate willingly though. Can the hen actually keep from getting her eggs fertilized?