Let's talk about leg color genetics

[Rebecca G Howie]

Have a hen with correct leg color who produced one chick with good color legs, but her next two have greenish/willow legs. One has yellowish skin and the other has skin (bottom of feet) that is about the same color as my skin but the top of the feet looks splotchy. The scales look like the tips are yellow.

Downsized images are pretty poor quality but may help. Chick 3 is 10 weeks, chick 4 is 7 weeks


Have not seen that with my other hen's chicks. I thought leg color was pretty straightforward with white skin and the dark scales that result in the slate color. Do I need to look at the cock as contributing to the color issue with these chicks? I need some "Leg Coloring Genetics for Dummies" here.


I have decided she and the pullet will go into the EE basket and the cockerels will be dispatched.

[Tailfeathers]

I'm not sure about the yellow skinned birds but I know the yellow leg gene is recessive and sex-linked.  I've linebred and inbred a closed flock for 8yrs now and I just had it turn up in my chicks last year so am hatching out a ton of chicks this year and will be culling heavily.  Because it's sex-linked you definitely wanna try to get a homozygous male(s) ASAP. 

That said, because it's recessive ya gotta take your birds where they are and weigh that out with your overall breeding plan and program to see how high of a priority leg color will be when it comes to culling.

For example, I have 3 males.  Two of them I think are heterozygous and one is I'm pretty sure homozygous for leg color.  I'm breeding the 2 hetero's because they're really good in everything else.  One of them is my avatar.  I'll likely wind up with 25% or so of yellow-legged chicks.  They'll go to folks who just want blue eggs.  Another 50% will be heterozygous with varying degrees of light blue to splotchy legs.  But hopefully I'll get 25% homozygous good legs and that's what will set me up for next year to be hopefully free of the recessive gene.

[Mike Gilbert]

Royce, you are partly right.   The yellow epidermis skin is recessive, but it is not sex linked.   See the Sellers link here:  http://sellers.kippenjungle.nl/page3.html

Dermal melanin IS sex linked and also recessive, so that is probably what you were remembering.   Sometimes these very young birds can show shades of yellowish in the leg color but then it disappears when they get older and they end up with slate colored shanks.   That in my opinion is a sign they are carrying one copy of w, so I tend to cull them whenever I notice it. 

[Suki]

Dermal melanin IS sex linked and also recessive, so that is probably what you were remembering.   

Melanin in the dermis is caused by a sex-linked recessive gene, id, in either the homozygous or hemizygous condition. The dominant allele Id (inhibitor of dermal melanin) is apparently only incom pletely dominant, for Dunn (1925) found some heteroZygotes with enough flecks of dermal melanin to give their shanks a pale blue cast.

The first evidence that the inhibitor of dermal melanin is sex linked was found by Davenport (1906) in a cross of Dark Brahma F (yellow shank) X Tosa M (willow shank) which yielded males all with yellow shanks and females all with willow shanks. Sex-linked genes were then unknown, and the significance of this case was not appreciated


 It seems probable that the sex-linked gene found by Bateson and Punnett (1911) to inhibit the peculiar black pigmentation of the Silky fowl is identical with the gene Id, considered here. Final proof that the inhibitor of dermal melanin is sex linked was provided by Punnett (1923) and Dunn (1925) between Polish willows and Leghorns, and later verified by Kaufmann in 47.


-----------------------Prof. Frederick Bruce Hutt, Genetics of Fowl, 1949
                             McGraw-Hill Publishers, New York

[Mike Gilbert]

Dermal melanin IS sex linked and also recessive, so that is probably what you were remembering.   

Melanin in the dermis is caused by a sex-linked recessive gene, id, in either the homozygous or hemizygous condition. The dominant allele Id (inhibitor of dermal melanin) is apparently only incom pletely dominant, for Dunn (1925) found some heteroZygotes with enough flecks of dermal melanin to give their shanks a pale blue cast.

The first evidence that the inhibitor of dermal melanin is sex linked was found by Davenport (1906) in a cross of Dark Brahma F (yellow shank) X Tosa M (willow shank) which yielded males all with yellow shanks and females all with willow shanks. Sex-linked genes were then unknown, and the significance of this case was not appreciated


 It seems probable that the sex-linked gene found by Bateson and Punnett (1911) to inhibit the peculiar black pigmentation of the Silky fowl is identical with the gene Id, considered here. Final proof that the inhibitor of dermal melanin is sex linked was provided by Punnett (1923) and Dunn (1925) between Polish willows and Leghorns, and later verified by Kaufmann in 47.
-----------------------Prof. Frederick Bruce Hutt, Genetics of Fowl, 1949
                             McGraw-Hill Publishers, New York

I believe I have an article in our Ameraucana Handbook on this subject - the one that was published in 1982.  It was mostly accurate, but would need to be updated if used today.

[Tailfeathers]

Well, as you well know I'm no geneticist.  As I said, I didn't know anything about skin color, though I assume it was recessive as well, but and just confirmed it on kippenjungle and a couple other sites I pulled up from a Google.  I didn't see anything about leg color so I went back to the main page glossary and Google it too. 

Everything I came up with on Google says that the yellow leg color is sex-linked and talked about "Id" being the sex-lined gene.  According to kippenjungle a yellow shank/yellow foot bird would be "w, Id, e+".  Here's the best thing I found on leg color.  Pretty detailed but it's 0400 and I'm gonna have to read it again tomorrow as my eyes are glazing over and I gotta get to bed or I won't get up for church tomorrow.

So in closing I'll just say I first heard of "sex-linked", and specifically the yellow leg being a recessive sex-linked gene back in 2013 or 2014 when I read an article in the PP where Kenny Troiano mentioned it.  I can also tell ya that since picking males with the best leg color for my Barnevelders and Welsummers, I've consistently gotten better leg color in my females. 

One other quick thing, on one of the pages of kippenjungle it says that there are "other genes" that come in to play for leg color.  Aside from mentioning a barring gene it leads me to believe they know some other gene(s) is effecting leg color but they don't know what.

Over and out...

[John W Blehm]

...but and just confirmed it on kippenjungle and a couple other sites I pulled up from a Google.  I didn't see anything about leg color so I went back to the main page glossary and Google it too...Over and out...

Keep in mind under our forum's Breeding subforum the Links to chicken genetics sites topic is pinned.  It gives me handy access to those sites without adding them to my crowded Favorites bar.  If you guys know of other sites that we should include links to there, please let me know.

Back on subject...my favorite site for "Leg Colour Genetics" is at http://chickengenetics.edelras.nl/.  It isn't lengthy, yet still gives a good overview.

[Mike Gilbert]

The Id/id allele has nothing to do with yellow pigment, sex linked or not.    It is what makes the dermis (inner) layer of skin white or dark.   There is no yellow in any chicken in the dermis layer of the shanks, which is the inner layer of skin.   That can be verified by posting a bird with yellow skin, cutting the skin around the shank at its' juncture with the lower thigh, and peeling back the skin.   On the yellow shanked bird, the dermis will be white.   On the willow shanked bird, the dermis will be dark - no yellow at all.   Since I described this procedure at the internationally used genetics forum at Classroom at the Coop, some have been calling this the "Bushman method."   I am Bushman there for those who have not guessed.   But getting back to Id/id, yes, it is sex linked.   The gene for yellow skin color (epidermis / outer layer of skin) is w, and it is recessive.  But w/W is autosomal which means it is not sex linked.     There is a sex linked recessive gene for white skin (y), however, but I have never observed it in over 40 years of breeding.  Here is a link to the Sellers site, page 3, that describes these various genes.   http://sellers.kippenjungle.nl/page3.html

[Rebecca G Howie]

Thanks so much for your responses! I have not been ignoring this but checking in and ( Thank you, John, Mike, Tailfeathers and Browneyes) doing more reading - all I can find. Just got a lot of extra grand baby time, so taking advantage of that. Was so stunned to see a leg color issue as I thought that leg color genetics in AM were stable at this point. I sure have so much to learn! This is harder than breeding horses . . .

Struggling with so much of the terminology. I don't absorb and process info like I did a few years ago 

This girl will be going to a friend who wants a bantam blue egg layer for her city backyard coop. Her leg color has improved greatly, but I still see the off color in places