G'day Deacons,
I had one of my hens lay an almost identical egg to the one in your photo. The hen was out all day the day before while I was working on the hen house so she didn't come in to lay. The next morning she laid the deformed egg and about ten minutes later she laid another perfect egg. I put it down to the second egg pushing against the first egg as the hen held it until the next day thus laying the two right after each other. She has never done that again, it sounds funny but I now know when she wants to lay a egg as she starts a sort of low pitched cluck as if she is talking to me.
Hope this helps you out.
Cheers
Paul B