Fertility cannot be determined through the shell. Development can, but not sheer fertility.
One must crack the egg to be sure, and then, of course, you cannot incubate it. Crack open some samples; if most are fertile, you have a good chance of incubating a fertile egg you don't crack open.
I guess its a wait and see thing cant really crack the others cause Im gathering them and am going to sell them. So I guess its one of these things
Yeah i have 7 silkie eggs and three of my Australorp Peachys eggs shes mated with my Dark Cornish Rooster so Im hoping something will hatch having a hard time seeing cause they shell is so dark makes me wonder how people can look in Maran eggs cause the shell is what like a dark chocolate color... So Ill see i guess. In the silkie eggs Ive got something going on its like only day three for them so still too early.. Thanks everyone