Jostling around can cause a fertile egg to have development stopped right at the outset, I think is what Sandy means. Unless you can crack it open later on during incubation and keep the yolk intact to check, there's not much way to know if it was fertile. After an egg is incubated, the yolk is very fragile and it's hard to open it and keep that yolk intact to examine it. Also, the blastoderm is sometimes on the underside of the yolk-one that's been incubated is really hard, if not impossible, to turn over to see that for verification.
I may offer more eggs when I have them to offer, if someone doesn't get a good hatch from eggs I've sent, however, I dont feel I'm obligated to do so. I think you'll find some members here who have received a second shipment from me, free of charge or for just shipping. I want them to have a good hatch from my eggs so I do everything I can to insure that, even if it wasn't my fault. However, obviously, so much happens from the time a rooster fertilizes an egg through the shipping then the incubation process, you'd be hard pressed to show that a seller has sold you infertile eggs. Then again, on occasion, an egg will be missed during the fertilization process. I've seen that with my own eyes-there will be one fertile then one not, from the same hen and rooster. Just one of those things.
