The Legbar Thread!

[ChicKat]

I have been studying to try to get up to speed on chicken genetics especially with regard to blue eggshell color, recessive white and color dilution since these are very relevant in Cream Legbars.

I came across a publication out of Beijing from January 2013 regarding blue egg color genetics: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3554524/pdf/pgen.1003183.pdf

It was quite interesting because it talks about the origins of the blue egg gene in chickens. They looked at Araucanas and two different blue-egg laying breeds of Chinese origin. The blue egg gene is inserted in different parts of the genome supporting parallel mutations in different chicken breeds.

They state in the article that the gene responsible for the blue egg color is inserted by a Retrovirus. The interesting thing is that retroviruses can cause disease in chickens but are associated with other mutations as well as the blue egg color. They listed some (pgs4,7) in the discussion session excerpt: "The effect of endogenous retrovirus (ERV) on hosts is extensive. It can unfavorably influence certain production traits, i.e. egg production, egg weight and body weight...and cause some phenotype variants, i.e. dilute coat color mutation [36] and hairless mutation in mice [37], recessive white [38], henny-feathering mutation [39], and the sex-linked late-feathering mutation [40] in chickens and outheld wing mutation in Drosophila melanogaster[41]. ERV could alter splicing patterns of transcript to produce variants such as the recessive white mutation in the chickens [38].

I need to cogitate on this a bit more and re-read, but I am interested in the potential linkage between the blue egg gene and the recessive white mutation. I have not read the references yet, but wanted to throw this out to the science geeks among us to see if they have a different take on what I read.

eta: One reference paper (French) talking about recessive white http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1373650/pdf/1471-2164-7-19.pdf states: "Finally, a rapid diagnostic genotyping test is now available to breeders, in order to identify heterozygous carriers of the mutation, which could be otherwise identified only by a tedious progeny-test." (pg 10) I will investigate if this test is available in the US.

Particularly interesting is the possible link between white mutation and blue egg gene -- Trish has whites and says that there is a clear sky-blue egg.

Also greatly interesting is that the blue egg can have multiple loci (is that the word I want?) - so perhaps some of the variations on blue could be that one place in the DNA gives a bluish green and one gives a greenish blue.

 

[ChicKat]

Thank you for the link! It is amazing the amount of different shades eggs can come in for just blue/green alone. Where would I go about getting an egg color chart? I really want to see where my egg color is. I really wished I had kept the eggs that these two hatched out of to compare to. This time around I will to see how they change with each generation. I am also going to crack one open to see if they are fertile and how much of a difference in color the inside is from the outside. Thanks!

In addition to Rinda giving the link to both the OAC color chart, and the Ameraucana club color chart, she has cross referenced the two charts -- they are posted in the Cream Legbar Club Clubhouse and also someplace here on BYC in one of the threads. :O)

 

[lonnyandrinda]

Yep, it's here. Someone pointed out there is one error on it but I haven't taken the time to track it down and correct it yet. This comparison sheet won't mean anything to you unless you have at least one of the color charts in front of you. Suggestions for improvement are welcomed.

Rinda

 

[Thespoiledchicken]

Particularly interesting is the possible link between white mutation and blue egg gene -- Trish has whites and says that there is a clear sky-blue egg.

Also greatly interesting is that the blue egg can have multiple loci (is that the word I want?) - so perhaps some of the variations on blue could be that one place in the DNA gives a bluish green and one gives a greenish blue.

Yes, my Whites lay such a beautiful sky blue egg

Only problem is so far they are terrible layers

Out of 2 White girls I'm getting 1-2 eggs a week (total). My 2 Cream girls are giving me almost 2 eggs a day! Eggs are blue to greenish though...

 

[KPenley]

Yes, my Whites lay such a beautiful sky blue egg

Only problem is so far they are terrible layers

Out of 2 White girls I'm getting 1-2 eggs a week (total). My 2 Cream girls are giving me almost 2 eggs a day! Eggs are blue to greenish though...

But...your eggs are really big!

 

[RyeRanch]

About the white gene and it's expression. Here is my experience with it. I had a white rooster and a hen who was a carrier. I was expecting to get 50% white offspring from this pairing. However, much to my surprise only about 10% of the offspring were white. This perplexed me that I was not seeing more white birds.

Then the white rooster was eaten by a coyote. Unfortunately, I did not have enough hatches to have any sort of statistically significant numbers or come to any conclusions. I thought there was maybe a higher mortality that may be associated with the whites. Or, I thought maybe I just sucked at counting.

So, I have a white hen and a white rooster who are about 1 month away from laying/ maturing so I can continue this experiment.

But, I do have a suspicion based on very limited experience that the a white legbar may be the result of a combination of genes or something more complex that just a dominant/recessive straight forward relationship.

Anyone else have anything similar? Anyway, very interesting that someone else has a much lower than expected appearance of whites.

I will update as the whites mature.

 

[ChicKat]

Yes, my Whites lay such a beautiful sky blue egg

Only problem is so far they are terrible layers

Out of 2 White girls I'm getting 1-2 eggs a week (total). My 2 Cream girls are giving me almost 2 eggs a day! Eggs are blue to greenish though...

So interesting. I have heard that the blue-egg layers in the USA, Araucanas and Ameraucanas are often low-volume egg layers. Also, that it is 'expensive' to the birds anatomy to lay blue eggs. The pigments required 'take more out of the hen'.

Some research with sea birds, noted a more saturated pigment in their eggs with increases in beta carotene in their diet. I have purchased beta carotene capsules, tried feeding carrots, and sweet potatoes to my hooligans..etc...to see for myself. My birds aren't big on their veggies..... They will turn up their nose if they don't like something. Perhaps supplying more beat carotene to the birds will give them what they need to produce more eggs? Just a thought..if their diet were to be altered, they would have more raw materials.

If green in the blue produces a greater number of eggs in a year, it is likely that there will be more birds hatched with genetic combinations that give that greenish blue. So -- maybe at some point we decide "what do I want?--- many eggs, or pure-blue eggs". Maybe some of each? I remember reading on a UK website, I think it was Emily de Gray's that they were hoping for 180 eggs per year....as kind of a standard. (an egg every-other-day). My pullet is laying at an amazing rate...her eggs are still small 1.6 to 1.7 ounces thus far. Yesterday afternoon - a high pressure flew through and the temps were 99-degrees with high humidity-- so the chickens were all panting -- so my egg production may go down due to the stresses now mounting on the chickens...but I do like those plentiful eggs. However, if she were to continue at her current rate she would exceed 180/yr by a lot, unless she were to go broody.

Seems to me like those of you who are observing these things and doing the research have noted that 1. pure-blue eggs will probably be less frequent than the bluish-green...so continuing the counts is going to be very informative. 2. Just because of the statistical rarety thus far from lonnyandrinda's and RyeRanch's flocks, there is a more complex genetic combination that simply recessive white producing the white chickens.

Thanks for contributing your insights --

ETA, if the white CLs are a marker for the pure blue - that could generate a market by itself. They are definitely very pretty birds - and if people wanted guaranteed blue-- then a white CL could be a good choice for them.

 

[1muttsfan]

It is always interesting to speculate on possible causes of different genetic traits. For an adequate genetic survey, you need a LOT of chicks hatched, and unhatched eggs have to be included in the reference population (to help determine if a trait is associated with early embryonic death). I have received quite a few shipped eggs that were a nice clear blue that were not from white birds. The greenish tint on eggs is due to the deposition of pigment on the surface of the egg, most likely due to some genetic impurities (meaning there were brown- or cream-egg ancestors somewhere in the background and the brown pigment was not vigorously selected against). Green eggs have just as much blue pigment as blue eggs, just altered in appearance by the deposition of pigment on the egg surface, so it is hard for me to believe that the blue pigment itself is causing lower egg production in just the blue egg laying birds. Instead, I think it may be related to either selective breeding for appearance without regard to egg production, that the breeds involved just do not lay as many eggs, or both.

 

[Thespoiledchicken]

But...your eggs are really big!

My adult layers that are all over a year old lay some monster eggs...bigger than any other breed I own. My Marans eggs look pathetic compared to my Cream Legbar eggs

 

[normanack]

. . . .The greenish tint on eggs is due to the deposition of pigment on the surface of the egg, most likely due to some genetic impurities (meaning there were brown- or cream-egg ancestors somewhere in the background and the brown pigment was not vigorously selected against).  Green eggs have just as much blue pigment as blue eggs, just altered in appearance by the deposition of pigment on the egg surface . . . .

I believe you are correct.

And yet. Why is it that my mint-green (Easter Egger) eggs are exactly the same color inside and out? (After the membrane is removed.) Is it just my eyes? Did long-ago bird researchers consider blue and mint green to be pretty much the same? FWIW different cultures divide colors differently -- apparently the Japanese used to put blue and green in the same category. I don't know if any of this applies, just musing.