So they would deprive humane, organic, free range envirowacko farmers of their livelihood just so they can feel self-righteous. And a good number of eggs not eaten would go to waste. If one were to let every single egg layed to be sat on, not only would there be an unsustainable amount of chickens (half of which would be roosters) and the world would be full of rotten, smelly eggs from the ones that weren't fertilized and spend their life under a very warm hen, getting "ripe" rather quickly. What about those poor meat birds? They grow so large so fast (I even let mine free range...or free waddle as the case may be and they still grow at a rapid pace) their legs can't support their weight. Think how cruel it is to allow them to live in pain with broken or sprained limbs because some stupid hippie wants to stroke his/her ego thinking they're saving the planet and Gaia's precious creatures.
Cindie