I've used Express and Priority with excellent results, and didn't pack them any differently than any other time. Express gets them there more securely as the packages are handled a bit differently, but it can still take 2 days.
I wouldn't worry about the shipping temperature if you use Express, but you should be sure they pack to prevent the eggs from lying sideways, as this causes the aircell to push the membrane off the eggshell on the sides. The eggs should be packed so as not to be able to shift at all.
I wouldn't worry about the shipping temperature if you use Express, but you should be sure they pack to prevent the eggs from lying sideways, as this causes the aircell to push the membrane off the eggshell on the sides. The eggs should be packed so as not to be able to shift at all.

