shell-less eggs from hen who has been laying for at least a month

[birdmomma]

So, I'm not certain who's doing the deed, but one of my BRs is all of a sudden laying shell less eggs on the floor of the coop. The group started laying in the middle of August, so I would have thought that the "kinks" would have been worked out by now. I have oyster shell always available, and try to feed back ground up shells at least 2X a week. Also this morning someone else deposited a very thin shelled egg that had odd ridges on it.... - any advice???
(we did have some hawk scares this week - could that have contributed?)

 

[JodyJo]

I just posted this question also...lets see what the pros say...

 

[RonB]

I wouldn't call this common. BUT its NOT unusual either ! I have a flock of 20 and I get a shell less egg once every two or three months. my girls range in age from seven months to two years. several people I know say the same thing. I have a Calif. White (2yrs old) that has not a laid a egg with a good shell in over five months. I have seen her laid a rubber egg or even no shell and then start to eat it. she seems healthy.
So I wouldn't worry too much about it

 

[dewey]

Do they receive layer ration? It sounds like it could possibly be diet related.

 

[birdmomma]

I have to admit that I feed them an organic mix - and it doesn't have the additives that Layena has in it. Guess I've been attempting to stay away from the GMO corns and soy. Doesn't the egg shell and oyster shell cover that?

 

[birdmomma]

All right - we have 8 BR hens - been laying for more than a month.

So this morning there was a shell less egg on the floor - it wasn't eaten; it looks like it was laid while one of the girls was on the roost, breaking when it landed.
And just now, the 8th girl laid her egg. . .
So there were 8 eggs laid today plus the shell less. Yesterday we got 8 eggs plus the 9th, a shell less egg. And this may have happened the day before that as well -
Can anyone offer an explanation what might be going on?