18 Eggs

In the Tibetan tradition Stein reports that:

In one variant of the egg legend...two birds are mentioned. There are eighteen eggs in their nest: six white, six yellow, and six blue (the colours of the three levels of the world and their deities). From the six middle eggs come men. Then three smiths appear, each belonging to one of the three realms-of the gods on high (lha, white), on earth (gnyan, yellow) and under the earth (klu, blue). To these three is added a human smith who comes from the middle realm.

Stein, R.A., translation by J.E. Stapleton Driver. Tibetan Civilization. London: Faber and Faber, 1972.