What makes eggs too porous?

[chickmanna]

Here is the picture from another BYC post of an egg that was too porous.

I ordered eggs from several breeders this last week and many of them resembled this picture, (spotty, mottled egg). Not quite this bad, but certainly not the solid shell I see from store bought egg and one of my own hen's eggs that I candled for comparison.

So what causes porous eggs? What effect does it have on hatchability? Do these eggs lose moisture more rapidly in the incubator, and is an adjustment to the humidity level necessary?

 

[quintinp]

I think it is lack of Calcium in the hens diet. I have recently changed from Country Lane brand chicken feed to Nutrena, and have started getting lots of eggs. They are very nice eggs too. What type of feed to you give your hens?

 

[chickmanna]

I feed Layena with oyster shell always available. My eggs have nice even shells, very glossy and substantial when I break one. The eggs I'm worried about came in eggs I had shipped in last week for hatching. I'm mainly wondering whether this is going to effect hatchability and if there is anything I should do differently when incubating these eggs - change humidity, etc.

 

[CapricornFarm]

I find porous eggs generally come from older hens. For the most part, I don't think it affects hatchability unless the shell is very thin. I have seen this topics on threads before, so you might want to do a search .;-) Deb

 

[billiejo21]

I've hatched shipped porous eggs and didn't see a difference in hatch rate. I've seen lots of threads about this too...not sure if there is any one thing in particular that causes it...