It's frustrating not knowing what exactly goes wrong with a hatch, and I think the number of possible causes and uncertainty goes way up when you are dealing with shipped eggs. I know I am frustrated with losing 6/10 orpington eggs by day 10. I'm guessing some of the Maran eggs are bad too, I just don't know it yet.
It's possible I did something to them because 1) incubator is no longer giving me accurate temps or humidity; 2) I should not have candled them on day 4; or 3) it was a bad idea not to turn them for the first couple of days (even though I read this was the right approached shipped eggs). I don't think any of these are the causes, but I guess I will never know for sure. I think it was old eggs, because of starting air sac size, or postal mishandling jumbled up the eggs. I wish I had put a couple of fresh eggs from my backyard in as controls.