Yeah, it is a large area but almost every place where u can go upstairs contains eggs and some hatchlings, there is also one 'cave' on the surface where eggs spawn. If hatchlings get killed by someone else, you can still observe the eggs in spawn place to know where you can expect them next time. I'll check my map if I had marked the spawns in Zao mountains, if I had it, I'll add it to the answer soon.
Also added link to the six ruby quest spawn, forgot to put it before.