Calcification on Eggs Shells Is Becoming Common... Ideas?

Hey there,

This week we've suddenly gotten four eggs that have bumpy shells, which appears to be calcification. Here are a few ideas I'm considering might be the cause. I'd appreciate your feedback, and any other ideas and advice.

The temperatures are below freezing outside, so twice we've found frozen water in the morning, despite our heaters etc. as the coop is ranging between 0 and -10 celcius during our coldsnap. I know that could be the problem, but it's happening even outside those incidents, though within the same week.

Their feed is commercial organic, they have free access to grit, and we provide kitchen scraps, including the shells of eggs we use in our home (not everything they lay, as we sell eggs). So I don't believe they'd have a calcium overload in their feed unless the commercial feed is off balance. Has anyone seen that?

We extend daylight hours with a 60 watt bulb and a timer, which hasn't changed in several weeks, so that should be ok.

I suppose something could be scaring the hens, but I haven't seen any predators lately.

For what it's worth, our hens are all between 6 and 8 months old.

Does my assessment seem consistent with what you'd examine in this situation? Have I missed anything?

Also, does anyone know if these eggs are safe to eat?

Here are a few photos. The rough eggs are in a line, with normal eggs from the same flock in a line below them for comparison. The variation in colour and size is because of the variety of breeds in our flock.

Thanks for your thoughts!

 

Thanks for the warm welcome, and the advice!

Yes, there are actual bumps on these four eggs. Other eggs are spotted, which is normal for our mix of breeds, but these ones are rough and bumpy, in addition to a slight change in colour on the rough area.

We have 11 layers, and it's happened 4 times in one week, so I'm suspecting it might just be one hen. Does that sound right?

We did change the feed from a standard commercial brand to an organic commercial brand about two months ago, but this problem is just starting to appear this week. Is it possibly a build-up?

I'm a bit unclear on the source of calcium in the feed. From what I understand it's in the layer pellet we feed. We also offer grit, which I believe is just rocks for their gizzard to act as teeth, but does it also contribute calcium? I wonder if that's creating too much in combination.

We're currently providing a bit more scratch (corn, etc.) than normal this time of year because of the cold weather as I understand that corn digestion helps them maintain their body temperature. Could that be lowering the protein ratio too much?

Glad they're safe to eat in any case!

Thanks again!