Odd egg colour

[angela0408]

It’s daisy! She was laying brown but she’s a young bird so maybe it took time to build up the color.

So this one does have a checkered past, so maybe someone in her ancestry has a blue gene.

 

[The Moonshiner]

7 pages deep and

 

[EmmaRainboe]

That’s butter, she’s a D’Uccle Cochin cross. 4 toes. Her babies were crossed with my silver laced polish. Those are the speckled ones. I have one polish/Silkie cross out there.

That wouldn’t explain the rose comb. Was the “d’Uccle” the father by chance?

 

[angela0408]

That wouldn’t explain the rose comb. Was the “d’Uccle” the father by chance?

Don’t know. The person I bought her from 6 years ago said that’s what she was.

7 pages deep and

Yup, still no answer why she’s switched from brown to green. We need a geneticist.

 

[The Moonshiner]

Yup, still no answer why she’s switched from brown to green. We need a geneticist.

Ok I know one. @aart
Wanna say it again?

 

[aart]

Wanna say it again?

Nope.
I can explain, have done so twice, but I can't make them understand.
<shrugs>

 

[NatJ]

Yup, still no answer why she’s switched from brown to green. We need a geneticist.

I've read a fair bit about genetics, and I've never seen anything that would explain this. A hen's genes make her able to lay eggs of a certain color. Her genes do not change during her lifetime, so her egg color should not be able to change either.

The amount of brown on the outside can change (darker or lighter, speckled or not), but if she lays eggs with brown on the outside, you would expect to always get some shade of brown. The same goes for blue in the shell: the shade or intensity might change, but whether it is present at all should not change.


I think the most likely explanation is that she never did lay eggs before, and only now started.

Or maybe she laid eggs with so much brown coating that you never noticed the green color underneath, and now they have less brown so the green is visible. (I think this is unlikely, but not quite impossible.)

If the blue (green) color requires some particular element in her diet, and if it was missing before but is present now, I suppose this could cause the change from brown to green. But I have never read anything linking dietary changes with a change in shell color, so I think this is probably NOT what happened.

 

[gimmie birdies]

My Black copper maran hen lays the egg in the lower right corner, but she also laid the purple egg, (just the bloom.)

 

[ButtonHoarder]

Maybe this got put in accidentally
https://www.rochesterhatchery.com/Poultry/heritagebreeds/AMER

I get my birds from there too, and I would really doubt that's what happened. Before this year, you couldn't order the "Heritage" breeds with any other breeds, which made me think they kept them in separate facilities.

 

[Ridgerunner]

I'm not a geneticist but the science behind this isn't that hard. Originally all chicken eggs were white, the color you get from calcium carbonate. There is no gene that makes them white, it's the natural color of calcium carbonate. Somewhere there was a mutation that caused the hen to add a blue pigment to the base color. This is a dominant gene so if just one of the two genes at that gene pair is "blue" you see the results.

The chemical process that creates this blue pigment is the same chemical process that causes the bile in the gall bladder to be blue. The raw material used for that pigment is recycled red blood cells, the same raw material that their body uses to make the brown pigment that coats a brown egg. Red blood cells are wearing out and being replaced all the time, the raw material is always available. It is a chemical process so other chemicals are involved, probably as a catalyst. I guess the intensity of that blue can change some, many of us have seen the intensity of the brown coating drop the longer the hen lays. But the chemicals for that blue pigment should always be available. When you butcher a chicken how often is the bile in the gall bladder not blue?

Typically the brown pigment is put on at the end of the egg making process, the shell is white underneath. But the blue pigment is added as the shell is made so it is blue all the way through. But there was another mutation where a gene can cause the entire white to have a brown pigment so that "white" shell can be off-white through it's thickness. The ones of those I've seen are pretty light brown throughout, sort of tinted but I wouldn't be surprised to see that shade vary a little. This tinting through the thickness of the shell can make these eggs harder to candle.

Anyway that's the chemistry as I know it. The genetics are that when the pullet is hatched she either has no blue-shell genes and will lay a base white egg. Or she hatches with one or two blue shell genes and will lay a base blue egg. It doesn't get much simpler than that.