She probably confused fertile vs non-fertile with free range eggs (where there is usually a rooster) vs caged eggs.
I don't think she did. I have heard this from several different sources, including the grocer at Whole Foods I questioned about stocking fertilized eggs. I do not have a problem with them, but was curious about the logic and price disparity.
The articulate answer I was given from individuals that sounded knowledgable was that the yolk/cholesterol is the food source for a developing chick, and that the embryo (while microscopic) has absorbed some prior to refrigeration.
Any scientific articles that I have found regarding the subject have come to the conclusion that there is no discernible difference in the cholesterol content of fertilized and unfertilized eggs. Likewise, there is no definitive link between cholesterol consumption and cholesterol levels. Ingestion of saturated and trans fats seem to play a much larger role in individual's cholesterol levels.
I would be thrilled if anybody else has links to any peer-reviewed articles to the contrary.
I am still looking for comparison between bird species eggs. It makes sense to me that if the variety of food items afforded to free-range chickens vastly improves egg quality, the different diets of ducks, geese, guineas, etc would yield different nutritional profiles. I have not come across a convenient informational source just yet, but will be happy to share when I do.