It spawns everywhere. I haven't gotten it yet either, but just because you haven't gotten it means it's broken.

Either way, I have confidence that Dusty would know if it was broken.

So, relax, you'll find it eventually.



On topic:

It's very, very easy to interrupt the egg trading process. I'm not sure exactly what causes it, but it happened to me a lot yesterday. I'm also not sure if this can be improved, but I hope it can.