Yes, it is normal for the eggs to be different. Each quail has her own egg pattern that usually doesn't change too much from egg to egg. I can tell who laid which because they have the same general color/spots/design. When they are newly laying the eggs might be fairy/fart eggs that are tiny, and might not have yolks. There is no problem if you get a few of these when they're new layers. Good luck with your quail!