I think it is the shipping, same thing happened to me a while back, I bought 7 blue copper maran eggs none hatched but my own I was geting 90% hatch rate too. sorry good luck with your two.
I had 2 eggs hatch recently, and placed 2 in bater just before the hatch but forgot the exact day, I had wrote on the eggs 2 weeks after the others hatched for when they were due, and then remembered it was not 2 weeks diff between eggs but just under 3 weeks. the eggs are doing fine though, and still veiny and moving. dang though I should have put a date on'm right away. I had to stager them because it was a last chance to get frizzles for me.