A few months ago I bought 2 female Valley Quail & 5 males. They all do fine in the cage together. You'd think the fertility was good... Well, I have only had 4 hatch & they are die on me... I raise many different breeds of birds so I know what to feed them and everything... I'm not sure how old they are... I am wondering if maybe there is something wrong with them... But they all look very healthy! Any advice?