No Yolk

Well, I've heard of eggs with double yolks. So far we haven't had one though. But I had never thought of an egg with no yolk.

I had another tiny egg the other day. A white one this time. So I cracked it into my skillet one morning with another larger egg for my scrambled eggs. And was surprised to see that there wasn't a yolk in it.

How does that happen? I'm not sure. Maybe you know.