These two eggs are from the same Coturnix, anyone know why they are different? Or has anyone seen this?
If you were to dissect a hen you'd see that the eggs form in a series in the ovaduct. There are usually 4 or 5 eggs forming inside a healthy quail hen. Sometimes one of the eggs moves through the process to fast or too slow and comes out miscolored. That color is actually pretty normal for coturnix hens.
Cots can lay quite a variety of colours, even from the same hen or strain. A while back I started saving the 'weirdest' of the bunch to take a photo of them all together. Enjoy. My quail normally lay eggs which looked like the ones on the far left/right. The top & bottom range is much rarer, usually during days of stress (summer heat, storms, etc) or change (after changing the litter). Though I can sometimes tell by the pattern who laid what. Like the bottom egg on the left of the pure white one. That one was laid by a little golden/wild mix I had. She almost always laid that pattern.