Why do hens lay unfertilized eggs?

With Easter just around the corner we will probably all be tucking into chocolate eggs very soon. But have you ever wondered about the non-chocolate variety that we eat… and why hens lay unfertilized eggs? It could be considered a fairly wasteful process; egg production requires protein, fat, nutrients and the calcium to make the shell. That’s a big investment for an egg that may not lead to any offspring. So why so many unfertilized eggs?

A bit of biology