I'll preface this with a bit of background.
I breed and ship live tropical fish  - for a living. I've shipped tens of thousands of boxes to all parts of the country (and other countries) in the dead of winter. My death rate on arrival is under 1% - way under 1%. I guarantee live delivery. If they don't make it, I pay for the shipping to get the next group there, even if it's late due to the carrier or weather. (Express mail and UPS Next Day) It can run over $100 per box. None of my competition pays for re-shipments - I get a lion's share of the business. 
Customers are looking for someone who knows what they're doing. They want as little risk as possible for their hard-earned money and will give it to someone confident enough in their shipping methods to give that guarantee - I am! And, yes they will pay more for this peace-of-mind. 
I experimented for months getting my packaging and shipping methods just right. I know my loss rate and am more than willing to lose money on some orders - it's simply good business to give the customer an iron clad guarantee - unless you can't figure out how to get them there in good shape - in that case you won't be getting much repeat business. 
I have experimented with packing eggs and I've come up with a method that will allow me to repeatedly kick the box about 10-15 feet (with my foot) and not have a single egg break. I've also found that air cells rupture more with certain packing materials and methods. 
Here is what I'll do when I start selling hatching eggs. 
I will guarantee unbroken eggs of the number ordered at the time of delivery. If broken, I will pay to re-ship the eggs. I will not advertise (extras if available) unless they are indeed available. - nothing more aggravating to a customer than to expect something and then not get them. 
I will not guarantee a hatch rate, but will tell them exactly what to expect from results of other shipped-eggs from the same group of hens. They will get a range that others have experienced   I will make sure this is very clear before the order goes out, and then will handle any serious non-hatch issues on an individual basis.  I have found that most people will reward generosity with future business and with recommendations to their friends. In the long run, it pays. You can't let a few people who will take advantage of your generosity, prevent you from being generous. Just accept the fact that some dishonest people will make out. 
In my fish business niche, most of my competition know exactly what I do (most have started with my stock), yet they still do not follow my lead.  They have not learned that superior customer service and customer satisfaction is a great way to increase your orders and thus the money you can make. 
This is not a stab at anyone in this thread who feels differently. It's just an overview of what I've found to work in business and how I plan on dealing with any hatching egg business I get in the future.