Extra shell

I have had chickens a long time, and never seen an egg like this.  there have been a few more similar to this, but not as bad.  Chickens have been laying a month or so.  It's always the almost white one.  There have been a few very large eggs the same color, they just look off.  Several times I have found like broken egg with no she'll in the covered area the eggs roll into.  It's not every time, so I'm hoping things will straighten themselves out. Just wondering if anyone has experienced this, or know what is going on.  Thanks

Same thing happened to me twice in the past few weeks...I was reading that it's calcium deposits caused by excess calcium in the chicken's diet. This is my Cuckoo Marans--I'm thinking she likes foraging for plants higher in calcium than the other hens. And I think soil-dwelling insects are pretty high in calcium--especially pill bugs and earthworms. Outside, everything has started popping in the last week and everything is coming alive--Spring is definitely here--and the chickens have been out more eating other things, so I don't think it's a coincidence.

Yup that happens to me too. Not all the time, but once in a while I get a rough egg like that and sometimes I get a shell-less rubbery egg too.

I've run into this a couple of times, its amazing the variety of things that can happen to eggs that most people don't see unless they keep chickens themselves.

As previously stated, this could be from chickens having excess calcium and doesn't effect the egg outside of the shell's texture. I have also heard that a stressed chicken can also produce these as they hold onto the egg for more time causing more calcium to be deposited by the shell gland.

I love it when this happens.  We used to get this on commercial eggs in the 1980s sometimes.  

It also means that my hens are getting enough calcium and can safely cut back a bit and save money on oyster shells.

If this happens often, it could be a defective shell gland. I was just recently reading about this and other odd egg issues. If it only happens occasionally, it could be caused by disturbances or stress during the calcification process. And yes, it can also be because of excess calcium in the chicken's diet. I would think that if not all the hens are having this on their eggs, the excess calcium thing may not be the cause? I was wondering about this myself. I am definitely not an egg-spert.

It often happens that my hens are giving me an egg with extra calcium, and occasionally I get one without a shell. I always have calcium available to them, so I figure that they occasionally indulge in more than they should have. I have Black Cuckoo Marans and Isa Browns and a mix of the two.
The fact that in the same flock I have extra calcium on some and no shell on the other leads me to think that it is a 'personal choice', and there's not much I can do about it.
There is one hen (ISA Brown) I'm monitoring closely because she had a "blowout" (Bleeding hemorrhoids). I separated her from the flock or they would have killed her, picking at her butt. I put her on a no protein diet (Nothing but greens and a little grain, some grit but no calcium) to completely stop her egg laying, and she did, immediately.
Now, she is 'cured' from her blowout and after 2 weeks, she started laying again, but eggs with no shells.
I put her back with the flock and after a few days, she started laying normal eggs again. Yesterday, I saw an egg with a spot of blood, so I will have to check on her, just in case.(They say that once they blow out, they are more prone to blowing out again.)
I think that hens may have a way to monitor the eggs that they put out, but it is probably limited.

I noticed that the brown calcium is much easier to remove than the white. Occasionally, if I pick at the white eggs bumps, part of the shell is removed along with it, resulting in an egg that is not saleable.
The Black Cuckoo Marans make a darker shell, and occasionally, when I see something on their shell that I decide to scrub, the whole color comes off (along with the bloom, unfortunately).
They are perfectly OK but they end up looking light brown. When they occasionally scratch such an egg, you see the scratch marks an a lighter egg is revealed underneath.
Does anyone know when the color is added in the oviduct? Is it at the 'bloom adding stage' of the egg?