Before moving to the country, and deciding to raise our own flock of birds, both for eggs and meat, my wife and I noticed that when we had bought "organic free range eggs", at a small farmer's market in SoCal, the eggs had yolks that were far more golden, in color, and creamier and richer in flavor. I did some reading, and found out that what I had deduced, was pretty true. When chickens eat a natural diet, of the food nature intended for them to eat, they produce more nutritious eggs. It was then, that we decided, once retired, and we moved to the country, we would have our own chickens, so we could always have those delicious, beautiful, golden yolks. Enough background. We are now a full year into raising our own moderately large flock, in rural Oklahoma. Most of our girls have started laying very well, since the winter slowdown (boy, was it slow) and we find ourselves with more eggs than we can even give away to friends and neighbors (most folks around here, have their own chickens), or hatch out. So, last night, I hard boiled 90+ eggs, to mix in to the feed, and feed it back to the chickens. In doing so, I noticed quite a few of them, that were quite bright yellow, a deep golden color, like we fell in love with, at that farmer's market. But many, were light yellow. So, I began paying attention. I have many different breeds, and can usually tell the eggs of one breed from the eggs of another, fairly well, by their color, shade, shape, size and sheen or lack thereof. While I can generally identify the Australorps, Jersey Giants, Dominikers, and Euskal Oiloas, pretty readily, from any others, the rest are pretty generic looking,mand difficult to say if it's from a black or red or gold sex link, or a Delaware, or an Orpington, or any of the several other breeds I have. The easily identifiable eggs, typically don't ever get hard boiled, as they either get eaten, or incubated. But, some of those that did get boiled, were more golden that others, and each of the more golden ones had the same traits. Telling me, that they likely came from the same breed. Now, my birds ALL have access to the same food. They eat high quality 20% protein supplemental food, in addition to their natural organic diet, from free range sources. None of them really ever stray very far from the coop, staying within 300' most all of the time, and much of that time, it's even closer. This leads me to believe that maybe some breeds convert their feed, more efficiently, into higher quality eggs. So, with that lengthy statement made, is anyone familiar with any study, or research, that proves, or disproves, my thoughts? Have any of you, experienced similar, and wondered? I grew up, and lived 53 years in Pomona, CA, the home of California State Polytechnic University-Pomona. It has a big AG program there. I wonder if it might be a worthwhile endeavor, to contact them, and ask if they know of any studies, on breeds, if we don't have that information here. Or, am I just plain nuts?