You’re right as well. I got all my shipped and it’s hard to know how long they have been on the road. I think that’s one of the biggest factor as to why eggs don’t make it. But that doesn’t mean it’s the only one.They usually aren't malpositioned when they hatch. These were shipped eggs and they had a rough ride + a couple of the OEG X that I incubated last were malpositioned.
If you want to assist:
https://www.backyardchickens.com/articles/step-by-step-guide-to-assisted-hatching.64660/
I had a gut feeling that they were going to be difficult. The eggs that didn't develop had a really thick outer membrane, I noticed when I cracked them to cook for the chooks; I had to rip them open. If they weren't so thick I don't think I would have been able to help much because they can tear and make the chick bleed out, this was a problem with every other time I've tried helping.
There wasn't really any way of telling exactly where they were going to pip at first. I just made sure they could all breathe when they needed because of the membrane concern. 11 have hatched with little assistance... 2 didn't make it.
Lots of variables to consider and hard to control as well. All we can do is make sure to check them and watch their progress.