I've purchased several sets of eggs from eBay. The first was from a bordering state - the shipping route took the eggs, during unseasonable cold, on a ridiculously circuitous route and I didn't receive them for several days. One had a hairline crack in it. None hatched. More recently, I bought some from a seller that lives less than an hour away and received them next day. Nicely packed, and all 11 were intact. Some were clears, one was a blood ring (14 days) and 6 made it to lockdown. 5 hatched. The third purchase was from a couple of states away, 16 eggs arrived. Nearly half were clears, 1 blood ring at 14 days. 8 went into lockdown, 7 hatched.
For comparison, I also set 6 of my own flock's eggs, 5 made it to lockdown, and 4 hatched.
Hatching shipped eggs seems to be a crapshoot. Some people report great hatch rates, others report very poor ones. There are a lot of factors that could influence hatch, as I'm sure you already know, but one of my purchased sets had an unacceptable number of infertiles. Your experience may be completely different, though. Good luck!