I've bought eggs once on ebay and had an okay hatch (3 to full development, 2 hatched. The other 7 were mostly stopped at day 7-11). But they also came from the other side of the country and we didnt set them correctly the day before incubating.
I hadn't even known birds could get sick before they hatched, so I hadn't worried about getting sick eggs.
I hadn't even known birds could get sick before they hatched, so I hadn't worried about getting sick eggs.