Clarifying Brown Egg Genetics

[draye]

Quote:
Never will a hen lay two different colored eggs. They will either lay white, brown, or blue. They on occassion, if they lay a brown egg, the next might be just a tad bit lighter brown.

 

[Naamahbengals]

Never will a hen lay two different colored eggs. They will either lay white, brown, or blue. They on occassion, if they lay a brown egg, the next might be just a tad bit lighter brown.

Will they lay different shaped eggs, then? If my EEs are ONLY laying green eggs and my orps laying all the browns, then the orpingtons are laying both 'plump' eggs, and smaller, more pointed eggs (same shape as the EEs lay) from day to day.

 

[draye]

Will they lay different shaped eggs, then? If my EEs are ONLY laying green eggs and my orps laying all the browns, then the orpingtons are laying both 'plump' eggs, and smaller, more pointed eggs (same shape as the EEs lay) from day to day.

Usually very little difference in the same, can variy a little. Orps don't all lay the same shape and size, all depends on the individual hen.

 

[Ridgerunner]

I may be wrong, but I don't think you can work backwards from green and brown and get blue. If you want blue, you need to start with blue. Someone correct me if I'm wrong

It depends on which brown genes are in the gene pool and whether they are split of pure for them. It’s possible to get bluer eggs but extremely difficult to consistently get true blue eggs. I know someone that has been working on this for 15 chicken generations after crossing brown into blue. In general the eggs are now pretty blue but she still gets a fair amount of green eggs when some recessive genes pair up. It makes it even harder when you don’t know for sure what the rooster is contributing.

Unless it is one of those dark layers that applies multiple pigments. Occasionally, often late in the laying season, not all of those chemicals are available. I can get very dark eggs most of the time and all of a sudden a hen will start putting out one or a couple weeks worth of light eggs. I assume that situation is nutrition related.

My comment about always laying the same color was about blue or white, green or brown, not the specific shade.

It’s pretty common for me that the shade of brown or green gets lighter later in the laying cycle. I’ve read that their store of pigments get depleted; I’ve read that the reason the eggs get lighter is that the eggs get larger but the amount of pigment remains the same so the pigment is spread over a larger area. The brown pigment is supposed to be derived from blood, but the way, just like the blue is derived from bile. I’m not sure what the real cause is, probably a combination of things. The brownest I see eggs is right after they start laying after a molt, even if the eggs are larger than when they stopped laying to start a molt. Sometimes those eggs are practically white just before they molt.

Since the majority of the brown is deposited last, if the hen lays an egg a little early (it doesn’t spend as much time in the shell gland as normal) less brown will be deposited. That’s why you might occasionally see a practically white egg from a hen that normally lays a darker egg. Something stressed her. But for that to happen over a two week period, something else is going on. I have no idea what.

 

[tadkerson]

Read this.

http://www.maranschickenclubusa.com/files/eggreview.pdf


It should help. I left out a study on a sex linked recessive brown pigment inhibitor found on the Z chromosome. It is found in white leghorns. My experience is that the gene may also dilute blue pigments in the shell.

Tim

 

[Ridgerunner]

That’s a lot to digest, Tim. I see I’ll have to rethink some of the things I thought I knew.

I’d always thought the blue shell color came from the bile. The way I know understand it is not that it comes from bile but the same process that produces the bile color also produces the blue shell color, and that the raw material for that are broken-down, old, worn-out red blood cells.

I’ve read before that there are 13 different documented genes that affect the brown shell color. The way I think I understand it now is that there are different dominant brown shell alleles but only one recessive brown shell inhibitor and only one dominant brown shell inhibitor. Maybe some are modifiers of the brown shell inhibitors or even some of the brown shell alleles? I’ve got a lot more studying to try to wrap my head around that part. I just know I’d hate to try to write the “if” statements in a computer program based on Table 1.1, especially with those yes or no’s in those blue and white boxes.

One of my take-aways from this is that it may not be as hard as I thought to get the brown or green out if you cross with a white or blue egg laying chicken and introduce those brown shell inhibitors. It still won’t be quick and easy, but maybe not 15 generations to get it done.

I’m still not totally clear on the color of the calcium carbonate shell itself. I’ve peeled back the membrane inside the egg to look at that shell from the inside on brown eggs. In most the shell is brilliant white, but I’ve seen some that are tinted maybe an ivory color. The way I read your article, some pigment is added to the palisade layer, which is the outside layer of the shell, not throughout the calcium carbonate shell. I understand a lot are added to the cuticle, or what I think of as “bloom”. I don’t see anything in here that would explain why I see that tint on the inside. Am I misunderstanding the palisade layer or missing something else?

Thanks for the article. I have a lot of study ahead of me.

 

[Sonoran Silkies]

Quote: All coloured eggs (non-white) fade as the laying cycle nears its end. Then the bird takes a break, molts, may raise chicks, etc. When she begins laying again, her eggs will be as intense a colour as they ever were. Sometimes in very old birds the colour remains faded.

 

[Sonoran Silkies]

Quote: Yes, a hen only lays the same colour of eggs throughout her life. Th intensity of the colour may vary, fading as her laying cycle completes, but when she begins laying again, the ful intensity of her eggs should be back.

 

[tadkerson]

That’s a lot to digest, Tim. I see I’ll have to rethink some of the things I thought I knew.

I’d always thought the blue shell color came from the bile. The way I know understand it is not that it comes from bile but the same process that produces the bile color also produces the blue shell color, and that the raw material for that are broken-down, old, worn-out red blood cells.

I’ve read before that there are 13 different documented genes that affect the brown shell color. The way I think I understand it now is that there are different dominant brown shell alleles but only one recessive brown shell inhibitor and only one dominant brown shell inhibitor. Maybe some are modifiers of the brown shell inhibitors or even some of the brown shell alleles? I’ve got a lot more studying to try to wrap my head around that part. I just know I’d hate to try to write the “if” statements in a computer program based on Table 1.1, especially with those yes or no’s in those blue and white boxes.

One of my take-aways from this is that it may not be as hard as I thought to get the brown or green out if you cross with a white or blue egg laying chicken and introduce those brown shell inhibitors. It still won’t be quick and easy, but maybe not 15 generations to get it done.

I’m still not totally clear on the color of the calcium carbonate shell itself. I’ve peeled back the membrane inside the egg to look at that shell from the inside on brown eggs. In most the shell is brilliant white, but I’ve seen some that are tinted maybe an ivory color. The way I read your article, some pigment is added to the palisade layer, which is the outside layer of the shell, not throughout the calcium carbonate shell. I understand a lot are added to the cuticle, or what I think of as “bloom”. I don’t see anything in here that would explain why I see that tint on the inside. Am I misunderstanding the palisade layer or missing something else?

Thanks for the article. I have a lot of study ahead of me.

I eliminated the brown from the eggs of the offspring of green egg layers in two crosses using white leghorns. But at the same time the blue was also inhibited. I did not attempt to increase the blue color in future offspring- I stopped the study.

I have experienced 6 different kinds of egg pigmentation
1. blue ( various shades) which is found within the shell
2. white with no pigmentation
3. green which is due to # 1 plus brown pigments on the surface of the shell
4. brown eggs with pigments on the surface ( shell itself is white)
5. tinted eggs that have brown in the shell ( just like a blue egg) with very little or no pigment on the surface
6. If an egg shell is smooth or chalky also effects the color hue

The whole biochemical process of egg pigmentation and the genetics are very complicated. There are a few newer studies out that deal with the genetic and biochemical aspects of egg coloration. I have not taken the time to analyze the new information.

I do what is referred to as meta-analysis with multiple studies- the egg review is a good example of this type of analysis. Making the information more easily understood is a challenge.

But you always do a good job of figuring out things. This diagram will help. Pigment is also added to the mammillary layer in some cases. I have seen this in one of my chickens; the inner shell ( mammillary) same color as outer shell layer (palisade). She was an easter egger- so may have something to do with the blue shell allele and the biochemical process ( just a hypothesis). In other words, she should be producing a blue egg but she is not. Biochemical reactions are rate dependent so if not enough of something is around the chemical reaction switches over to another pathway producing another product. Could be the blue pigment pathway was switched off to produce a small amount of brown pigment (blue pigments are produced from brown pigments). Research indicates small amounts of brown pigment are produced while the blue pigments are being produced and vise versa.

Tim

 

[Ridgerunner]

That diagram helped a lot as did your list of 6 pigmentations. The #5 I saw, tinted, were from Cackle hatchery stock, crosses of Speckled Sussex, Delaware, and probably Black Astralorp. I’m not sure of the exact parentage, but as far as I know, no EE’s in the background.