Here is an example of studies about the nutrition of a coturnix egg:
Coturnix eggs are characterized by a variety of color patterns. They range from snow white to completely brown. More commonly they are tan and dark brown speckled or mottled brown with a chalky blue covering. The average egg from mature female weighs a bout 10 grams (1/3 ounce), about 8 percent of the body weight of the quail hen as compared to 3 percent for chicken eggs. The egg of Japanese quail contains 158 Cal. of energy, 74.6% water, 13.1% protein, 11.2% fat, and 1.1% total ash. The mineral content includes 0.59 mg calcium, 220 mg phosphorus and 3.8 mg iron. The vitamin content is 300 i.u. of vitamin A, 0.12 mg of vitamin B1, 0.85 mg of vitamin B2 and 0.10 mg nicotinic acid.
Like I said, coturnix quail eggs are far superior to any other quail egg, nutritionally speaking. Notice that it has 300 i.u. of vitamin A, and CalorieKing does not list any vitamin A whatsoever in store bought chicken eggs. Notice also the higher protein content. When we did our research, there was a lot of sites with nutrition information that we could find, and so we averaged out what they all said for Corturnix quail eggs (not any other kind of quail egg like Calorie King used,) and came up with the 8 times the nutrition of a regular store bought egg. If I find time later to look up more sites, I will try to list them, as I know that we found them to be extremely interesting.