Apparently Dr. Suess wasn't crazy!
Green eggs are very real. They come from "Americana" chickens.
In addition to a dozen regular eggs, I just picked up the last dozen of the green ones at my local farmer's market. According to the seller, they are smaller, but MUCH richer in flavor, to the point that some people say they are almost TOO flavorful. They are also, as a result, much higher in wonderful nutrient content.
Can't wait to crake into these bad boys when I make dinner and see what all the fuss is about!