Quote: Bulls eyes indicate that the semen from the rooster entered the yolk, it does not necessarily mean that his semen is viable. The test is whether you are getting chicks or not. No chicks means the roo isn't fertile. Rooster sometimes go through infertile periods. Cold, too hot, maybe he is sick but not enough for one to notice. Put in another rooster & see if he makes chicks. If he does, then you know your original rooster isn't fertile for whatever reason. Or, sometimes a hen will not let a rooster breed her. But, you will get fertile eggs from the other hens in the flock. If you can separate a hen, mark her eggs, and then see if they develop, you will know if she is letting the roo breed her or not.
Shipped eggs are another matter all together. Who knows what they go through in transit. I find that Marans eggs for whatever reason, don't take shipping as well as other breeds do.