Next you'll be saying that all carrots taste the same. Or wheat (my grandfather was an elevator operator - it doesn't at all according to his account, due principally to local soil conditions - different geology.)

Science isn't whatever meets your expectations. While the egg isn't functioning as one big working cell, it's not made of cells, it is what became of just one cell. More here if you want the discussion. https://www.reddit.com/r/askscience/comments/ry2ug/are_chick...

As for what healthy eggs looked like, I'm guessing you haven't spent much time on a farm. The fragile, rather sickly eggs you're so used to buying now were unknown on farms fifty years ago, when I was younger.