This article from Mother Earth News is outstanding. Their nutritional testing concludes that:
Most of the eggs currently sold in supermarkets are nutritionally inferior to eggs produced by hens raised on pasture. That’s the conclusion we have reached following completion of the 2007 Mother Earth News egg testing project. Our testing has found that, compared to official U.S. Department of Agriculture (USDA) nutrient data for commercial eggs, eggs from hens raised on pasture may contain:And later in the article they do address the sorts of misleading statements that the Iowa State University researcher made in the Modern Marvels program. Go read the whole thing.
• 1/3 less cholesterol
• 1/4 less saturated fat
• 2/3 more vitamin A
• 2 times more omega-3 fatty acids
• 3 times more vitamin E
• 7 times more beta carotene
These amazing results come from 14 flocks around the country that range freely on pasture or are housed in moveable pens that are rotated frequently to maximize access to fresh pasture and protect the birds from predators. We had six eggs from each of the 14 pastured flocks tested by an accredited laboratory in Portland, Ore. The chart at the end of this article shows the average nutrient content of the samples, compared with the official egg nutrient data from the USDA for “conventional” (i.e. from confined hens) eggs.
I should mention that here in Michigan there is very little for our free range hens to forage on in the winter. They do eat our table scraps, but we must supplement their diet with layer ration from the feed store. We hope to remedy this in the future by growing more "winter keeper" feeds such as pumpkins, mangals, and other squashes that can be broken open for our hens when the pasture is gone.
Thanks again to Sara for directing me to this article.