If you have quail, and especially coturnix quail you know they have a high calcium requirement due to their high egg production rivaling the most productive chicken breeds. Regardless of what you are feeding, your quail hens probably need more calcium than the commercial feeds can give them, and their eggshell quality will start to suffer. If you are getting eggs that crack or break easily or even eggs with no shell, then your quail hens need more calcium. You can grind the egg shells from eggs you use and feed them back to your hens but often this is not enough. A trip to the feed store will reveal bags of oyster shell. Most will sell smaller bags in the 5-10 pound range, I've bought them for around $6 for a five pound bag. Sure it will last a little while, but see if they have it in a 50 pound bag. I can get a 50 pound bag for $14 at my local feed store! Oyster shell does not go bad, will not get buggy, so why not get a large bag? Then you get it home and open the bag and realize the pieces are chicken sized. How are our little quail hens going to eat those? There are two ways of making them edible for our quail. One is sifting, which is good if you have chickens too. Go to the thrift store and buy a strainer/colander with holes small enough to pass chunks and powder through it. Don't use one your significant other wants since the oyster shell will eventually ruin the finish. This one has holes small enough to get quail sized pieces. Make sure before you start to work with the oyster shell you put on a dust mask. And plan on doing this outside with the breeze blowing the dust away from you. This is a very dusty job and you don't want the dust going in your lungs or getting in your eyes. Now sift the oyster shell with your strainer over a large bowl. The small stuff will be suitable for quail to eat. The large stuff left in the strainer is great for your chickens. You will end up with about one part quail sized to 5-7 parts chicken sized particles of oyster shell. Store it in a convenient location so it will be ready to use daily.