The celadon egg gene is a single gene. Celadon eggs in quail are similar to celadon eggs in chickens it's a result of internal biology. If you read the blue eggs section on this site it gives a general description. This site gives a much more scientific viewpoint but is a hard read.
As of right now hatching and breeding only blue eggs has not led to an increase in the expression of the ce egg gene for anyone I've talked to.
As of right now hatching and breeding only blue eggs has not led to an increase in the expression of the ce egg gene for anyone I've talked to.