I think it is incredibly nice, OP for you to send replacement eggs. I don't think I would. I'm a total newbie to this, so correct me if I'm wrong, please. When shipping eggs (especially during the winter when temperrature fluctuations from region to region are huge), the buyer assumes that they are taking a gamble. I know that there is no 100% way to check fertility prior to shipping, and that some may not be fertile, I know that shipping is hard, and subjects the eggs to temperature fluctuations, a great deal of movement, and possible abuse. I would not assume that the seller is responsible, and should thus replace my eggs, if things weren't going well. There are just FAR too many variables that cold occur AFTER they leave the seller's hands.
Is this wrong of me to assume? I really don't know anything, as my first set of shipped eggs are in the incubator now!