For the shells, from boiled eggs, just let them dry, and crush them in coffee mill, and add them to the bird feed. That is what I do. The ones from raw eggs, I put them in the oven after done baking, and let the cooling oven cook them, before crushing to feed back to the quail.
Quail eggs contain more fat and protein by weight, double the iron and riboflavin, and about one-third more vitamin B12 than chicken eggs. On the other hand, chicken eggs contain more choline. Quail eggs are also more difficult to find and more expensive...
Kiki, my bad batch of White Wing Pharaohs, I got all but one as white wings. The one white one, I had to move out of her cage, as her hatch mates tried to kill her. She is doing good now.