Shipped eggs are one category. Eggs that came in the car to you ( or any car) are a middle zone, but an hour in the car wont stretch the membrane. I think its the planes that do it. The expanding and contracting. I know this is not a popular answer ( in fact its an darn annoying one) But, if you want to get your eggs perfect for your incubator, I would weigh AND watch humidity outside to see how it is affecting your incubator. And adjust your humidity and even temp accordingly ( we are talking tenths, maybe) IF you really want 100% hatches. What you need to know is what temp and humidity will get your eggs to 3% a day ( I THINK!) weight loss. It is the real way to know EXACTLY what is wrong. That being said, it sounds like your hatch is going fine, just slow. I would be content there. We had a mini chicken Miracle today! MY frilkie rooster disappeared 3 days ago. Took me a day to realize it, and we looked up and down the creek for 2 hrs ( one in the dark ) on Sunday. I have been trying to wrack my brains about what I could do about that coop, if it is not safe, I don't know how to cover it, as its on a hill and not level. He showed up this morning!! At the stairs and agitated and skinny! I guess he jumped the baby gate getting chased by the other roos while I was collecting eggs. He has a new name now... Leif Errikson!