Flaky eggs?

[aart]

That was my first thought but that seems even more curious for one of them to try wrapping up a white egg in a brown shell. The white egg was fully encapsulated in the brown before I removed them from the nesting box.

I seriously doubt the 'wrapping' was intentional, just a fluke of scratching around in the nest.

 

[Ridgerunner]

Check this out:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5803769/

Thanks Kiki, I really appreciate that. I'm not going to pretend to understand all of that but it is written in a surprisingly easy to understand language for that type of study. I got a lot out of it. The bottom line is that they don't know for sure when or where but suspect it's in the shell gland and late.

I'll copy a few of what I consider important comments. The scientific name for "bloom" is "cuticle".

Experimental evidence supports the location of cuticle deposition to be the shell gland pouch (uterus), not the vagina, and the time of deposition to be within the final hour before oviposition.

We demonstrated that the quantity of cuticle was a heritable trait in chickens

Where the cuticle is formed appears to be contentious. There are online articles on avian reproduction stating that it is formed in the vagina but proof seems limited for the assertions made.

The evidence is best for the formation of cuticle in the shell gland

Another unanswered question is when is the cuticle deposited?

Finally, although we know that genetics contributes to variation in the amount of cuticle deposited on an egg [2], the influence of environmental factors on its variation has not been investigated.

We got an even more confounding egg today. It appears to be an extra large fully formed thin shell egg with a fullmsize hard shelled egg inside. When I checked the nest box, the thin shelled outer was already broken and egg white and yolk had soaked the straw.

This is really rare but an egg in an egg happens. It is called counter-peristalsis contraction in case you want to look it up. I don't know what causes it but an egg gets sucked back up into the internal egg making factory before it gets laid and another egg forms over it. You usually get a yolk and egg whites outside the first egg.

That would make sense with your egg. The pigment is the last thing to go on the egg so if it is sucked back up early it is still white. It forms an extra large egg so what shell material the hen has needs to cover a bigger surface which means it can be thin shelled and break easily.

If this was a one-time thing I'd say wow, you are lucky to see this really strange thing. To me it looks to be different from what happened with your other egg. If it is the same hen that laid both, I'd think there is something screwed up with her internal egg making factory. The eggs are still good to eat but may look weird.

I don't know of any disease that would do this but I certainly don't know everything. Most veterinarians are not avian vets, they are unlikely to know anything about this. I did not notice you saying where you are located. If you are in the US I'd be tempted to call your county extension office and chat with them. When I was in Northwest Arkansas my local extension office put me in touch with a poultry science professor at the University that had some really expert knowledge. Maybe you'd get that lucky.