My (unasked-for) contribution is that, beyond shipping safety, the best thing you can do to ensure hatchability is to feed a nutrient-dense, high-protein diet to your layers. 16% layer doesn't really cut it for great hatching eggs. I'm not sure if you already knew that, but a lot of people don't really think about it, so I'm just tossing it in there.
@sylviethecochin i actually didn't think of that, but considering it... my birds actually get alot of food supplements in their diet all the nieghbors and friends donate their food and leftovers so in addition to the birds getting feed, freeranging, and our orchard I also allow them chick feed during molts and some pigeon feed for the good oat and grains, plus corn, plus any leftover fish, mice, mealworms(live) from our other animals so i should hope my birds hatchability is good! Although I will note I lost some of my older girls this year so I dont know how eager my younger year-long girls are breeding wise. But from the eggs ive cracked they are at least generally fertile.
@john_wrightson2003
Depending on the shape of the eggs upon arrival in the last shipment going out. I may send more as I assure the most successful shipping method. I'll pm you if it becomes a possibility