xanthrophyll

[John]

A chicken\'s skin color can be changed (temporarily) by diet.  It doesn\'t affect the feather color/pigment as some claim, but the natural yellow pigment xanthrophyll, that is in plants, changes white skin and scales yellow.  It is added to Perdue brand chicken\'s feed to produce a yellow skin for marketing reasons.  If your Ameraucanas eat fresh alfalfa their skin will take on a bit of a yellow tint.  This will also change their egg yokes to a darker yellow and the pads of their feet to a willow or yellowish color.  Feed marigolds for the best results.
Chicks get their nutrients from their egg\'s yoke for the 21 days of incubation and for up to 3 more days after they hatch.  If the yoke is rich with xanthrophyll they may hatch with yellow feet where it would genetically be white/flesh color.  My breeders only get 100% game bird breeder pellets during the time they are producing hatching eggs, so when I have chicks that hatch with yellow foot pads I cull them knowing it is hereditary.  Others are feeding their breeders grass and other supplements to their diet that cause chicks to hatch with yellow foot pads.  These change to the proper color within about 4 weeks, since it is just from the temporary pigment that migrates from the plant to the hen to the egg to the chick.
This seems to be a logical possiblity as I understand it.  I don\'t know of any scientific experiments that have been done to prove this, but we know for sure that the pigment affects the skin of the chickens and egg yokes.  The assumption then is that it also affects the chicks.  
What say you?
Thanks to Mickey DeTour - Purdue University, Cal Flegal - MSU, Anne Foley and Paul Smith, for their input and thoughts on the subject.

[Paul]

  I see a day old black, blue or splash chick with a yellow foot bottom which turns snow white by four weeks of age as no different from a wheaten, blue wheaten or splash wheaten day old chick with white shanks which turn slate by three months of age; especially if there is a possiblility that the temporary yellow was caused by the hen\'s diet, which laid the egg that produced the black, blue or splash chick with the temporary yellow foot bottoms.

[Mike Gilbert]

I tend to agree with Paul.  I pay no attention to the leg and skin color of newly hatched chicks.    I cull for skin and leg color, if necessary, at about 4 to 6 weeks of age.   The exception would be whites and silvers.    Their legs should be dark when they are hatched;   but they could turn out to be willow instead of slate, so I look at them again at 4 to 6 weeks.   Never saw a black, blue, black gold, or brown red chick with anything other than dark legs at hatch.

[Anne Foley]

I also agree with Paul.  The development of pigment is a complicated business.  The process of getting from A to Z doesn\'t matter so much as the final result.  We know a person who breeds White Ply. Rocks.  There have different lines that produce different colored chicks.  It is the final product that matters, not what you see in the beginning.

[John]

I know the Standards only describe mature birds, but a mature bird that meets the standard may be masking undesirable genes that may show up in their chicks.  That is why many will tell you that a champion in a show may not be the best breeder.
Consistent looking chicks are desired.  It saves many months of disappointment if you know what to cull for in day old chicks.  If it is obvious that the chick is lacking muffs, has the wrong type comb, wrong down color or pattern, shank color,  etc. they should be culled.  Some traits cannot be used as criteria to cull for until the birds are older and those traits appear, such as eye color, shank color in wheatens and buffs and adult feather color and patterns.
The change in the shank color of recessive wheaten varieties is due to genetics whereas the temporary yellow foot pad color is due to diet.
I know that my breeders don\'t get an extra dose of xanthrophyll so I will continue to cull chicks if and when they hatch with yellow foot pads.  If your breeders are consuming high amounts of xanthrophyll, then don\'t cull chicks for yellow foot pads...allow time for the temporary pigment to go away.
Other than that I would recommend culling early on for everything else.  The photos of day old chicks on the Photos page of the website should make it easier for everyone to know what to look for.  
I\'m only suggesting we don\'t cull do to the affects of xanthrophyll.  Remember that xanthrophyll can also change the skin (including foot pads) and scales of mature birds.  I\'m saying don\'t cull them either if it is only a temporary pigment.  
Those affected won\'t meet the Standard (temporarily), but may produce show quality chicks.   Don\'t show them either until it goes away.  
 

[Guest]

All my birds are free range and when chicks are still in \"brooder stage\" I hand graze clover and grass for them. (All my birds graze heavily.) While I do not have alfalfa, I do have plenty of clover. I have been test breeding all my roosters for yellow legs (I purchased Ameraucana breeding roo.s which were both carrying yellow legs!) and I cannot cull newborn chicks by footpad color. At about 2 weeks, I can discern willow legs as the quality of \"yellow\" is different than the the \"tinged\" color of the newborns foot. Hard to explain, but I would say the yellow skin is an obvious opaque color, whereas the color of the newborn is clear.
There has not been much study of the genetics of skin color. I\'ve spoken with several breeders who have given me their advice based on years of breeding. I\'ve certainly wondered if w/W+ does express in some way (in the same way that many genes co-express). Perhaps when you have a diet with xanthrophyll and w/W+ is when you see the yellow \"tinge\" coming through more? Interesting stuff ... wish we had more hours in the day.

[John]

Perhaps when you have a diet with xanthrophyll and w/W+ is when you see the yellow \"tinge\" coming through more?

Or is it that sire (w/W+) mated to dame (w/W+) is producing some chicks (w/w) that are pure for yellow skin.  And if that were so why would the yellow disappear after 4 weeks of age?
White skin color (W+) is dominant over yellow (w).  According to http://marsa_sellers.tripod.com/geneticspages/page3.html W+ \"Prevents the transfer of xanthophyll into the skin, beak and shanks but does not effect the eye iris, egg yolk or blood serum\".  If that is true then I would think that the chicks that hatch with yellow foot pads may be w/w from parents that are w/W+.  If so I would go back to my old game plan of culling them.  With \"w\" being recessive it could be hidden in a flock for years and came back to haunt us like other recessive genes.  Trap nesting (test mating) would be the only way to make sure birds don\'t carry it.    
The two university poultry experts that I talked to about xanthophyll only said it can change the skin and scales of chicken without mentioning anything about W+ restricting or preventing it.
:stare:

[Guest]

You have to remember that genes have on and off switches (gene regulators). In the case of pullets, when the pullet is inside the egg  the switch turns on the white skin gene and inhibits the addition of yellow pigment to the skin,etc.. Once the pullet is older then the switch is turned to off, (turns off the W+) allowing dietary pigment to be added to the skin and shanks.Storing the pigment so that it can be added to her eggs later.

Once the pullet starts laying eggs, the dietary pigment will be drawn from the shanks and skin and placed into the yolk of the egg. The more eggs she lays the more yellow pigment will be removed from the skin and shanks. She will go back to white shanks etc. Males are a different story. Once they have the pigment, I know of no mechanism that would remove the pigment.

I have written two articles on shank and feet color. If you are interested go to

 http://home.earthlink.net/~100chickens/
 
Click on shank and feet color in the side menu

Tim

[John]

Tim,
I like both articles and really like your chart.

Once the pullet is older then the switch is turned to off, (turns off the W+)

It sounds like you are saying W+ inhibits yellow skin pigment only during certain periods in the life of the bird.  From my understanding W+ doesn\'t inhibit xanthrophyll from expressing it\'s yellow in the yokes, but does in the skin and haven\'t read anything about it being turned on and off.  I have not seen a white skinned bird develop yellow skin regardless of age or diet.
I understand that some E locus genes such as recessive wheaten don\'t allow shank color to express itself in very young chicks.  In that situation all the chicks will hatch with clear/white shanks/legs, but they all turn dark within a few weeks.  
If all our black and blue Ameraucanas are based on extended black (E) with white skin (W) then all the chicks should hatch with white (clear, pinkish, flesh colored, etc.) foot pads as I understand it.  Why would some chicks, from the same flock, hatch with yellow pads while the majority hatch with white pads?  
Taking the hens diets into consideration I would think that even if W+ doesn\'t express itself until the birds are older then all our black and blue chicks would hatch with yellow foot pads, not just a few.  

[Guest]

John,

It sounds like you are saying W+ inhibits yellow skin pigment only during certain periods in the life of the bird.  From my understanding W+ doesn\'t inhibit xanthrophyll from expressing it\'s yellow in the yokes, but does in the skin and haven\'t read anything about it being turned on and off.  I have not seen a white skinned bird develop yellow skin regardless of age or diet.

I was trying to give a possible explanation why one would get yellow in the shanks when a bird should have white skin.

Why would some chicks, from the same flock, hatch with yellow pads while the majority hatch with white pads?

Taking the hens diets into consideration I would think that even if W+ doesn\'t express itself until the birds are older then all our black and blue chicks would hatch with yellow foot pads, not just a few.

It would be interesting to see if the chicks with yellow foot pads  are heterozygous for white skin , W+/w. One or two birds in the flock could be carriers of the w yellow skin gene and a person would never know that they carry the recessive gene. The only time the recessive gene would show up would be when two carriers produced chicks. You would have to have a male and a female that carried the recessive yellow skin gene. As long as the females were carriers, the yellow skin would not show in the flock.

I have not noticed this in my birds. Most of the birds I work with have yellow skin.

Tim

[John]

It would be interesting to see if the chicks with yellow foot pads  are heterozygous for white skin , W+/w. One or two birds in the flock could be carriers of the w yellow skin gene and a person would never know that they carry the recessive gene. The only time the recessive gene would show up would be when two carriers produced chicks. You would have to have a male and a female that carried the recessive yellow skin gene.

That I can agree with 100%.  

[grisaboy]

I have yellow or willow legs that pop up now and then in my silver bantams.  I introduced the yellow legs a few years back when I added a very nice colored Auracana hen with beautiful blue eggs to the flock.  I also have white legs that came from Old English.  I cannot tell white legs from yellow legs in the newly hatched chicks.  This may have more to do with my own eyesight, but to me they all look pink.  Also, I have found that some of those pink legged chicks will turn to dark legged chicks after a couple weeks.  By the time they are 4 weeks old I can see very clearly what they are and cull the ones with the wrong leg color.  I have not hatched any with yellow or willow legs this year, but I have several very pretty birds with white legs that will soon be moving on.

Curtis