Random blue spots on green egg

[eeldien]

Hello all. My green queen popped this egg out today and I thought it was really weird. I just want to see if this is something that can happen occasionally to eggs or if there is something else going on. Below is a picture of the egg she produced today. Generally her eggs range from a light olive green to a light army green. I thought these spots of blue were random and was wondering about what might cause such a phenomenon…

 

[DemeterAD9]

Blue should be the underlying color, the shell color. Brown pigment is added over the blue shell to make green eggs so my guess is a minor glitch in the process. Young or old hens will have an odd egg here and there.

 

[ChickenCanoe]

Has she only ever laid solid green eggs?
It may help to understand how pigment is applied to the shell.
The blue pigment is applied during the process of calcium application. This is evident from the hint of blue on the inside of blue, green and olive eggs. Then (except for some rare breeds) brown pigment is applied after the shell is fully formed. The genetics of blue egg layers dictate when and where in the uterus the pigment glands are.

 

[eeldien]

Has she only ever laid solid green eggs?
It may help to understand how pigment is applied to the shell.
The blue pigment is applied during the process of calcium application. This is evident from the hint of blue on the inside of blue, green and olive eggs. Then (except for some rare breeds) brown pigment is applied after the shell is fully formed. The genetics of blue egg layers dictate when and where in the uterus the pigment glands are.

Yes- she has only laid green eggs. She is about 3 years old and is one of my most consistent egg layers. Thank you for the info about when the color is applied during the egg formation process. You all are so knowledgeable!!

 

[ChickenCanoe]

I've studied egg color pigment for quite some time. Sadly, there is very little scientific research on the subject. Nearly all I have been able to discover is on normal brown eggs and also the blue pigment. There is virtually none on dark eggs. Personal research tells me that breeds other than blue egg layers apply pigment at an earlier stage of shell formation. The breed I raised, Penedesencas, laid one of the darkest eggs. I discovered the inside of their shells had some of the dark brown pigment. I don't know if other dark egg breeds do. I know Welsummer's don't. But perhaps there is some of that in Maran's or Barnevelder reproduction.