wrinkled shell?

[Gonzo]

On of our hens lays large, long eggs. Often, theres some wrinkling at the top of the more narrow end of the shell. The shells themselves are hard, but there's wrinkling. What causes that, and should I be concerned?

 

[MontanaMomma]

I got one of those the other day. But I don't get them regularly. Your chicken only lays these??

 

[gritsar]

I wouldn't be concerned unless your bird shows other signs of illness.
Here, this might help you determine the cause:

http://www.thepoultrysite.com/publications/1/egg-quality-handbook/18/misshapen-eggs