Shipped eggs are just hard.
My last two shipments arrived the same day, one set had a cracked egg in it and that set never even started. The other set of 8 eggs, I got five very cute little silkies out of - three cheers for Cjexotic. Four blues and a black. Five of eight is better than 60% I think but I'm not doing the math lol.
I'd get more eggs from CJ any day. My best hatch was a shipment of turkey eggs, they had one broken in the box, but all the others did hatch. Poults are fragile and one died after hatch but that was a 100% hatch. Those rested almost three days before they were set.
It takes fiddling to see what works with shipped eggs and your incubator/set up. They're funny fragile hopeful little things aren't they? Frustrating and heartbreaking too but I try to overlook that part.
Both times I got marans eggs some disaster happened and I lost all of them but one. Ginormous power failure the first time and then a temp spike 134, the second time and the temp spike I STILL got one to hatch. Her name is Faith.
I think in a lot of ways hatching is about faith.