Thoughtful breeding with a few surprises...

[NatJ]

I don't see any reasonable way that could be from Recessive White genetics.

If the roosters are New Hampshire and Delaware, I would not expect either one to have recessive white or extended black. The Delaware would have white barring.

So if one hen was black, hiden by recessive white, she could produce a black chick like that. Barring could be either from the hen or from the Delaware rooster.

I agree with your explanation about how Dominant White could be involved, just saying that recessive white is also a way for a white hen to produce a black chick.

With only one black chick, I'm thinking there is just one hen producing that color, and she did not produce many total chicks. I presume she is either one of the White Rangers or else one of the White Plymouth Rocks. I'm leaning toward the Ranger, because it sounds like there were fewer Ranger hens than Rock hens, but I'm not positive, and I'm not sure whether she is actually Dominant White or recessive white.

I'll post the genetic path this weekend...

Did you post it yet? I can't seem to find it.

 

[SE_Gardener]

Didn't mean to keep folks hanging on this for the rest of the story, weather has been challenging here on my homestead. As I mentioned, my intent was to hatch out a few eggs to test specific hens with my two roosters. A note about culling/selection of breed stock. I select short stocky roosters w/ deep chests, broad flat backs, substantive legs and big feet. I also look for a large deep head. I don't care about anything other than that phenotype, fast fleshing and consistent offspring. I don't care about breed perfection - I'm breeding for meatbirds. See pics of roosters below - two very different breeds but bred to have consistent phenotype. I'm sure you'll agree they both have very similar physiques - it's not a mistake.

(#1) NH Rooster is F2 from Freedom Ranger Hatchery. I'm confident my NH are purebred and at this point are a closed flock.

The hens I was testing was my best NH hen and a White Ranger Hen to cross with #1 NH Roo. The NH hen is from my closed NH flock 4/1/2024 - I don't doubt her breed purity. The White Ranger hen is from Freedom Ranger Hatchery 4/1/2024. From my research the White Ranger is shared genetics project between Hendrixs/Hubbard (Cobb500 Male) and Sasso (Sasso White Broiler Male X Sasso heritage bantam line hen).

I've really struggled trying to reconstruct my Delaware breed flock after 2023 depopulation. Not bashing hatcheries, but they have really $hitty Delawares. I keep buying, raising, culling, crossing. I can't seem to get past the egg-type in creating a meatbird roo. So the best I was able to produce after a lot of effort is this boy and wanted to test his purity and see if he carries both dominate and recessive white CC/cc and also the silver allele that the Livestock Conservancy was able to isolate and preserve in their recovery efforts. This guy came from a known hatchery who contracts hatch eggs from a producer who raises Delawares from the Livestock Conservancy progeny. So I'm confident my Delaware roo is pureblood and likely carries the white genes and silver allele. To validate I crossed him on a meatbird-type Ply White Rock hen and expected to hatch a Delaware colored chick. My Ply White Rock were obtained from a known hatchery that has been producing this breed for several decades. I buy my rocks from him and they are always consistent. I keep six as my layer flock. All of those hens exhibit the silver allele and I'm confident are purebred dominate white.

So when the little black chick popped out with the white dot on his head, I had a pretty good idea of what had happened. I reached out to the TN Ag School poultry guys to discuss genetics just to make sure I was on solid ground. I believe this little black chick is the result of Atavism - a potential throwback to the Barred Plymouth Rock male ancestry in the Delaware bloodlines. Atavisms are prompted by the rare reactivation of genes that previously controlled phenotypic features lost many generations ago. The following is the genetic basis for that determination.

The Delaware breed originated from a Barred Plymouth Rock male and a New Hampshire (George Ellis) or Rhode Island Red female (typically backyard flock owners). As a sport of that cross, their feathering is not Columbian (another genetic discussion) but a specific arrangement of genes producing white body w/black barring on the hackle, wings, and tail. The barring is due to the B (barring) gene that could be B/B or B/b, where b is the non-barring allele). He only needs the B which is sex-linked and carried on the Z chromosome (males are ZZ, females are ZW). The Delaware male will ALWAYS pass his white-based plumage with black barring to his F1 offspring, both male and female, regardless of the hen crossed.

White Plymouth Rock females are homozygous for recessive white (c/c), which suppresses pigmentation, resulting in solid white plumage. They lack the barring gene (b on their Z chromosome) and do not contribute significant color genes beyond the recessive white.

So the F1 progeny from my Delaware Roo and Ply White Rock should have Delaware feathering of white body and slight barring. Of the two fertilized eggs hatched one appears to be Delaware (I'll have to wait for the first chick molt to validate) and the little black chick.

So the little black chick must express significant black pigmentation (E/E or E/e for extended black) and the barring gene (B). His white dot is a hallmark of the B gene, especially in males, as it disrupts pigmentation on the head.

My Delaware roo could contribute the B gene (barring) and possibly a recessive e or E allele (from his New Hampshire ancestry) that allows black pigmentation. However, the White Plymouth Rock female contributes c/c (recessive white), which should suppress color, and lacks the E allele for extended black.

So for that black chick to appear, his gene writing typewriter would need to somehow bypass the dominant white (I) or recessive white (c) genes that both parents carry, allowing the black pigmentation (E) and barring (B) to express. A rare genetic wrestling match mixing recessives and dominate genes to some how overwrite the genetics of the Roo and Hen, and come out looking like an ancient male ancestor.

The TN Ag professor agrees with my hypothesis of atavism and suggested an even rarer possibility could have taken place like a spontaneous mutation or rare recombination event that allowed the black pigmentation (E) to express, bypassing the I (dominant white) or c (recessive white) genes. He said it is less likely but possible in small populations where recessive genes can surface unexpectedly.

Without spending $ for genetic testing of the Delaware roo and the Ply White Rock hen, I'll accept the Atavism. Hopefully this discussion will demonstrate things happen when breeding chicken and developing a strain of meatbirds is not easy.

So why did I go through all this? My goal is to cross Delaware roo one time with White Ranger hens to produce a F1 hybrid breeding hen, that when crossed on the NH roo will produce F2 broilers (my version of color yield) and ultimately achieving sustainability. Trying to cross commercial F2 hybrids will always produce great variability and often not give you what you're looking for. You need to spiral cross to produce your own F2 hybrid. But I've learned that you can cross a commercial female hybrid like Cornish Rock, Freedom Rangers, White Rangers, etc with a heritage purebred like Delaware one time and produce a fairly reliable F1 breeding hen with meatbird genetics with an identifiable feather coloring. That F1 hen can then be crossed on another Heritage purebred like NH producing consistent F2 meatbirds. Similar to the spiral breeding found in the Cornish Cross broiler.

So I've proved that my Delaware roo will be a good candidate to cross one time on White Rangers. I'm currently raising 25 to process and butcher the male F1 and cull out the best F1 females to be my breed stock to cross on my NH Roo. With consistent culling those offspring should stabilize and I can then close my sustainable flock for 3-4yrs. Then have another Delaware and NH Roo in the wings to do it all over again.

Here's the birds I tested. Both roo are down in weight feverishly breeding this spring and the hens are pretty torn up. I'm growing out their chicks with the White Rangers and in a couple months, I update what these two roosters produced on these 3 hens.

 

[NatJ]

I believe this little black chick is the result of Atavism - a potential throwback to the Barred Plymouth Rock male ancestry in the Delaware bloodlines. Atavisms are prompted by the rare reactivation of genes that previously controlled phenotypic features lost many generations ago.

If atavism just means that the person breeding the chickens has produced a chick that doesn't appear to make sense, then yes that fits.

But if atavism is meant to be something that cannot be explained by the usual actions of the usual color genes, then no your chick is not the result of atavism. Your chick is the result of completely normal interactions of several common genes that are acting in the usual, predictable ways.

The following is the genetic basis for that determination.

I think part of your explanation is wrong, and the person at the college didn't help either.

What you said in another thread here was correct:
https://www.backyardchickens.com/th...er-with-white-rock-hens.790644/#post-28467446

Yes, Delawares have barring. They also have the Silver gene, and the Columbian color pattern (with white barring breaking up the black sections into dots.)

Delaware...is not Columbian (another genetic discussion) but a specific arrangement of genes producing white body w/black barring on the hackle, wings, and tail. The barring is due to the B (barring) gene that could be B/B or B/b, where b is the non-barring allele). He only needs the B which is sex-linked and carried on the Z chromosome (males are ZZ, females are ZW). The Delaware male will ALWAYS pass his white-based plumage with black barring to his F1 offspring, both male and female, regardless of the hen crossed.

Correct about the barring, but I'm not sure what you mean by "not Columbian." Do you just mean they are barred + Columbian, or do you mean something else?

Delaware... carries both dominate and recessive white CC/cc and also the silver allele that the Livestock Conservancy was able to isolate and preserve in their recovery efforts.

You seem to have a typo in the abbreviation. Dominant white and recessive white would be II/cc.

You also have an error, because Delawares do not have domiant white, and your rooster does not show recessive white. So he is probably ii/CC, but could possibly be ii/Cc.

Dominant White turns black into white. Delawares do not have Dominant White. Those bits of black in their coloring are the proof of that.

Recessive white turns the whole chicken white. If Delawares were recessive white, they would not have those black dots.

Delawares have the Silver gene. No need to test, no need for special work from the Livestock Conservancy, you can tell by looking at them: that is where all the white in the body comes from. If they didn't have Silver they would have gold, and would have large amounts of gold or red color (like a New Hampshire but with white barring added.)

White Plymouth Rock females are homozygous for recessive white (c/c), which suppresses pigmentation, resulting in solid white plumage.

Yes.

They lack the barring gene (b on their Z chromosome) and do not contribute significant color genes beyond the recessive white.

I can't say if they have barring or not, given that the recessive white hides it all, but you might be right about that.

As for whether White Plymouth Rocks contribute significant color genes: they definitely do if they are bred to a rooster with no recessive white! Once you produce chicks that do not show recessive white, they do show the effect of whatever other genes they inherited from the White Rock, which in this case includes E (Extended Black).

So the little black chick must express significant black pigmentation (E/E or E/e for extended black) and the barring gene (B). His white dot is a hallmark of the B gene, especially in males, as it disrupts pigmentation on the head.

Yup.

My Delaware roo could contribute the B gene (barring) and possibly a recessive e or E allele (from his New Hampshire ancestry) that allows black pigmentation.

Yes on the B (barring), yes he contributes one of the recessive alleles at the e-locus.

However, the White Plymouth Rock female contributes c/c (recessive white), which should suppress color, and lacks the E allele for extended black.

Since recessive white is recessive, and the hen gives only one c gene, then no that will not suppress color in the chick, because the chick inherits C from the father. On the other hand, if the hen has cc (two genes for recessive white), she herself would be white no matter what genes she has at the e-locus.

Given that the chick has E, and the Delaware father does not, it is pretty obvious that the White Plymouth Rock hen does have E.

So for that black chick to appear, his gene writing typewriter would need to somehow bypass the dominant white (I) or recessive white (c) genes that both parents carry, allowing the black pigmentation (E) and barring (B) to express. A rare genetic wrestling match mixing recessives and dominate genes to some how overwrite the genetics of the Roo and Hen, and come out looking like an ancient male ancestor.

Nothing so complicated.

The chick does not have dominant white (I), because the Delaware parent is ii and the White Rock parent is either Ii or ii.

The chick does not show recessive white because it inherited C from the Delaware parent.

The chick inherited E from the White Plymouth Rock parent, and barring (B) from the Delaware parent, and those are what shows in its coloring.

It doesn't take a "rare genetic wresting match," it is a perfectly normal result in that situation.

The TN Ag professor agrees with my hypothesis of atavism and suggested an even rarer possibility could have taken place like a spontaneous mutation or rare recombination event that allowed the black pigmentation (E) to express, bypassing the I (dominant white) or c (recessive white) genes. He said it is less likely but possible in small populations where recessive genes can surface unexpectedly.

No new mutations are needed.

"Bypassing" I (dominant white) is not needed when the chick simply does not inherit that gene.

"Bypassing" c (recessive white) happens any time you breed a chicken with recessive white to a chicken that lacks the gene: chicks have only one recessive white gene, and that has no effect on their coloring.

Without spending $ for genetic testing of the Delaware roo and the Ply White Rock hen, I'll accept the Atavism.

No need for the genetic testing. Just keep producing chicks from that hen and lok at the results. If you breed her to the Delaware rooster, about half of her chicks should be black with white barring. The more you hatch, the more confident you can be that the results are repeatable.

Or if you want to breed that hen to the New Hampshire rooster, at least half of chicks will be black that way too. Sons from that cross might show barring (if the White Plymouth Rock hen has barring too) or might not, but you'll get that answer once you have some chicks that show E (Extended Black.)

My Ply White Rock were obtained from a known hatchery that has been producing this breed for several decades. I buy my rocks from him and they are always consistent. I keep six as my layer flock. All of those hens exhibit the silver allele and I'm confident are purebred dominate white.

If they are pure for recessive white, looking at them will not tell if they have the silver allele or dominant white.

Given that this hen produced the black chick, she could be Ii or she could be ii, but she certainly is not II (pure for dominant white).

Of the two fertilized eggs hatched one appears to be Delaware (I'll have to wait for the first chick molt to validate) and the little black chick.

I can think of several explanations for the white chick.

It might be Delaware colored, which would mean the White Plymouth Rock hen is E/?, with one allele for Extended Black and one allele that allows the chick to show a Delaware-type coloration.

Or it might be white all over.
The white chick might have Ii (dominant white from the mother turning all black into white, none from the Delaware father). That would mean the White Plymouth Rock hen is Ii.

Or the white chick might have cc (recessive white from both parents, which would mean the Delaware father is carrying it even though Delawares usually don't.)

Either dominant white or recessive white would turn the chick white no matter what alleles it has at the e-locus.

I'm growing out their chicks with the White Rangers and in a couple months, I update what these two roosters produced on these 3 hens.

I'm definitely curious to see how the chicks grow up, especially the black one and its full sibling.

And if you breed more chicks from that White Plymouth Rock hen, I'd be especially interested in what colors they are. (And if they show that I'm the one mixed up about the genetics, I definitely need to learn that before I spread it further!)

 

[SE_Gardener]

Thanks my post was informational. If you don't agree, take it up with the geneticists at Tennessee State University Ag School, Poultry Division. I will not be responding to replies.

 

[NatJ]

Thanks my post was informational. If you don't agree, take it up with the geneticists at Tennessee State University Ag School, Poultry Division. I will not be responding to replies.

I must have misunderstood your first post. I thought you were inviting discussion.

In that case, I'll just watch for updates.

 

[SE_Gardener]

I must have misunderstood your first post. I thought you were inviting discussion.

In that case, I'll just watch for updates.

I spent an enormous amount of energy and time setting out the details of the chickens bred, my validations of their breed purity as well as a straight forward conclusion of professional geneticists which confirmed my research. Genuine discussion, yes. Sentence by sentence critique/challenge to the veracity of the geneticists is not subject for discussion in terms of accuracy/correctness. Frankly as I said, the event of atavism is extremely rare and I merely thought people would find that interesting. I'm not up for forum debating. I'm sorry you disagree with the Univ of TN geneticists.

 

[NatJ]

I spent an enormous amount of energy and time setting out the details of the chickens bred, my validations of their breed purity as well as a straight forward conclusion of professional geneticists which confirmed my research.

And I was trying to address it directly and clearly, so there would be no confusion about which parts I was referring to.

I'm not up for forum debating. I'm sorry you disagree with the Univ of TN geneticists.

If you don't want to discuss it, I'm happy to just drop the matter.