I'm confused. You mentioned that you've raised quail for 10 years in your opening post, but in the above post, you say you've never raised quail? Anyways, I would like to see pictures of your Valley x Mountain hybrid hen that is currently laying. Although I am open to learning new things, I am finding it difficult to believe you. Valley and mountain quails are both wild species and they do not mature in 8 weeks (~1 3/4 months). Instead, they mature and start laying eggs the following year. At 8 weeks, they are only almost half grown. Now if you were to say coturnix, then I wouldn't have anything to say. I raise both species and in the past, when there was an accidental cross (male mountain x female valley), the hybrid offspring's growth rate was the same as chicks from both the parent species. I agree with Cel45 that that egg is big for a quail. You might have made a mistake and that egg may have been laid by a chicken.