Chicken Canoe is right in that you need to monitor your eggs! I like candling, and have a pretty strong LED light where I can see into most eggs. The ones I can't, I just go by the others in the bator that I can see into.
That said, shipped eggs are always a gamble and can often have unseen damage that lowers your success rate. I know some people have had good hatches, many have had poor hatches, and I can't tell you how many people have only ended up with one or two chicks out of 2 dozen set. Distance, heat, altitude change, shaking, dropping, etc can all do a number on eggs.
Dark eggs are less permeable due to the dark coating, so starting at a lower humidity can often help.
Good luck!