The humble egg is now a source of frustration for millions of shoppers around the U.S, who face soaring prices and shortages. What's going on?

If you’ve been grocery shopping recently, you may have noticed a lot of bare shelves in the egg section. And if you’ve managed to snag a carton, you probably spotted something even more shocking: the price.

Egg prices have more than doubled over the last two years as a dangerous strain of bird flu has swept across the country.