Getting the occasional fertilised egg is a risk you take if you get proper free range. it's no big deal (unless it's your last egg), you can also occasionally get eggs that have a soft membrane instead of a hard shell round them, they'll never make it to the shops but if you have your own chickens you'll see them (the membrane eggs are perfectly OK to eat.)
You just have to accept that nature doesn't always make things exactly as we'd like them to be.
How awful. I would never eat an egg again. Come to think of it I don't like eggs so it would not occur. Thanks for your warning ummmm - I didn't have a look.
Horrible things really eggs. I occasionally eat one that has been bashed around and covered in tomato sauce, but they look revolting and are slimy nasty things.