What's been stamping this egg?

[HAfewtchie]

Does any one know where the circular imprint has come from:/?
The dent came from being in my pocket !
Looking forward to the answer cos I have no idea

 

[Ridgerunner]

Check this out. What probably happened is that one egg was delayed getting laid so long that another egg was formed and put in the shell gland for its shell to be laid on before the first one was laid. If it only happens once don’t worry. The egg laying process is pretty complicated and weird stuff can and does sometimes happen. If it becomes a regular occurrence then you might look for a cause.

http://www.thepoultrysite.com/publications/1/egg-quality-handbook/19/flatsided-eggs/

That shell looks pretty thin. That’s another sign that the second egg might have started its journey through the hen’s internal egg making factory early. The shell gland did not have enough time between eggs to make enough more shell material to lay on enough shell material. This is often the cause when you find a random soft egg though getting one marked like that is fairly unusual. Again, not a cause for concern unless it is a regular occurrence. Weirder stuff than this happens and is not really a problem.