My husband and I imported standard BBS orpington eggs from England about 1.5 years ago. It was not difficult in one aspect because the UK is free from END, so getting the permit was pretty simple. However, it can be much more difficult to get hatching eggs from some of the other countries that are not free of END.
Depending on the # of eggs you import, and how many different shipments, it CAN be very expensive. The time in transit is a huge factor. One of our shipments of eggs did not arrive until 12 days after shipment from England. I think we had 5 or 6 different shipments before we finally got 2 chicks to hatch - luckily we hatched a cockerel and a pullet.
As per our experience when importing eggs - hatching eggs from the UK do NOT have to be quarantined. (There are other countries where the eggs do have to be quarantined for 30 days - the 30 day quarantine is AFTER the chicks have hatched and the chicks are then tested. The eggs also have to be quarantined and hatched in a USDA approved place). The fees for importing hatching eggs from the UK are relatively small. The permit fee was $137. It takes about 7-10 days for the application to be approved. You can fill the application out on-line and then fax it to the USDA. The permit is good for only 30 days and for one shipment only regardless of the number of eggs you have imported. You have to get a new permit for each shipment of eggs. You do have to get a vet to test the breeders birds (usually at your expense) and fill out the proper paperwork. I think (if I recall correctly) there are 3 specific things that they are testing for. (I think the vet certificate is good for 90 days, but don't hold me to that). When the eggs come in to the US, they have to be inspected by a veterinarian and that price can be anywhere from $35-$125, depending on if there is a vet on site at the particular port of entry. You can choose which port you want your eggs to arrive (choose one with a vet on site), but you do have to call 72 hours prior to arrival of eggs. Once the eggs have been vet-inspected at the port of entry, you can either pick the eggs up or have them shipped on to you. The ports that have a full-time vet are listed on the APHIS website. All the info is on the APHIS website. If you call them, they are very helpful in walking you through the entire process and giving you all the necessary information. I found them to be extremely helpful and nice.
The biggest problem we had when trying to import eggs was finding a breeder that would work with us...it took us about 1-1/2 to 2 years to find one.