It really does make a big difference in how they packed and how far away they have to travel. If your buying eggs I'd make sure to find out how they will be packaged.
I bought eggs from way out northwest, 3 day priorirty, seller packed them all pointy end up...I think one was packed right...every single one rolling air cell and with good incubator I surprisingly still got 12 to hatch out of 36....I think 18 went into lockdown, I didn't turn these at all for the first week. These were tissue wrapped in egg carton, then egg carton wrapped and one box with crumbled newspaper.
Got 14 eggs from Jacksonville FL to southeast AL. 2 day priority. 2 quitters, 2-3 I think aren't developing, leaving about 9 that are developing right. None of the air cells were detattached, one saddly aircell, and that one that egg quit. Eggs bubbled wrapped and in carton, double boxed with more newspaper.
Got 21 eggs from CA. 3 day priority, 6 polish all developing, 15 guinea eggs and only about 5 that aren't developing. Packed superbly, bubbled wrapped eggs in carton with shredded paper taking up extra space in carton. Cartons double box with packing peanuts between boxes. The box even arrived with one size dented and no cracked eggs.