Shipping eggs does affect the hatch rate. If they have a good trip to you then you might only lose a few eggs, but if they have a rough trip then you'll be very lucky to get anything to hatch.
I hatched shipped eggs and eggs we picked up (3 hours drive from us) at the same time in the same incubator. Out of the eggs we picked up 9 out of 10 hatched. Out of the shipped eggs only 3 out of 8 hatched (and they were all cockerels). I tried again with shipped eggs from the same person, ordering 12 (thinking I might get 4-6 to hatch) and that time they must've had a good trip as 9 ended up hatching successfully.
If you can find a private breeder it's worth the trip to pick the eggs up rather than leaving them to the mercy of the postal system.