Why Are These Chicks Black If The Father Is A White Plymouth Rock?

[nicalandia]

The post from nicalandia would assume that the mother of those possibly female chicks was barred or cuckoo.

Not necessarily,

E/E, B/B rooster mated to none barred female will yield Heterozygous Barred males(B/b+) and Hemizygous barred females(B/-), the males will still be identifiable from the females, females have a faint barely noticeable headspot, males even with heterozygous Barring(B/b+) will have a larger undefined headspot the will extend to the back of the head area just like your typical sex link chicks..

Black Sex link chick(E/eWh B/b+ chick)

 

[Cyprus]

Not necessarily,

E/E, B/B rooster mated to none barred female will yield E/? B/- Females and B/b+ males, the males will still be identifiable from the females, females have a faint barely noticeable headspot, males even with heterozygous Barring(B/b+) will have a larger undefined headspot the will extend to the back of the head area just like your typical sex link chicks..

Black Sex link chick(E/eWh B/b+ chick)

Awesome. Thanks for the clarification.

 

[NatJ]

E/E, B/B rooster mated to none barred female will yield Heterozygous Barred males(B/b+) and Hemizygous barred females(B/-), the males will still be identifiable from the females, females have a faint barely noticeable headspot, males even with heterozygous Barring(B/b+) will have a larger undefined headspot the will extend to the back of the head area just like your typical sex link chicks..

Black Sex link chick(E/eWh B/b+ chick)

I think you've got that backwards. Black sexlinks come from a non-barred rooster bred to barred females (example, Rhode Island Red rooster with Barred Rock hen): so only the sons get barring (head spot), and the daughters are all black (no head spot). I don't see how you'd tell a male with one copy of barring from a female with one copy of barring.

For the OP's chicks:
If the White Rock father is barred (hidden by the white), then all chicks would carry one copy of barring. The chicks who have a barred mother (Marans, Delaware, Barred Rock) will have a larger yellow spot on the head IF they are male (because a male can have two copies of the barring gene, B.) Any female chicks, and any male chicks whose mother was not barred, should have a smaller or not-present head spot (because they'd only have one copy of B.) The chick from the Easter Egger, for example, will not be sexable by head-spot.

 

[nicalandia]

I think you've got that backwards. Black sexlinks come from a non-barred rooster bred to barred females (example, Rhode Island Red rooster with Barred Rock hen): so only the sons get barring (head spot), and the daughters are all black (no head spot). I don't see how you'd tell a male with one copy of barring from a female with one copy of barring.

Extended Black(Homozygous or Heterozygous ) Males will have a larger uneven heaspot that extends to the back of the head(that is why I referenced the black sex link video so you and everyone can see the E/eWh, B/b+ chicks, dot pay attention to the female black chicks without barring)


Barred Rock Chicks can be sexed at hatch with good accuracy because the female headspot are small even shaped that only stay at the top of the head.

Statistically speaking 50% of the following chicks are females, can you try to tell which one is female and which one are males?

Perhaps my vision is too sharp but I can tell which one is male and which one is female.

 

[NatJ]

Extended Black(Homozygous or Heterozygous ) Males will have a larger uneven heaspot that extends to the back of the head(that is why I referenced the black sex link video so you and everyone can see the E/eWh, B/b+ chicks, dot pay attention to the female black chicks without barring)

Barred Rock Chicks can be sexed at hatch with good accuracy because the female headspot are small even shaped that only stay at the top of the head.

I thought the reason one can sex barred rock chicks or sexlinks is because the headspot size depends on how many copies of B are present. B/B in barred rock male is two copies (big headspot), B/- in barred rock female is one copy (little headspot). Sexlinks are B/b+ male one copy (little headspot), b+/- female no copies (no headspot). Which means a black sexlink male (B/b+) looks just like a barred rock female (B/-) (little headspot).

The barred rock males in the video have TWO copies of barring, so they are not a good example of what ONE copy of barring looks like.

 

[nicalandia]

The barred rock males in the video have TWO copies of barring, so they are not a good example of what ONE copy of barring looks like.

Hence the video I posted about the Black Sex Links(with B/b+ males) in Extended Black background(Homozygous and Heterozygous) a single copy of Barring will give the same headspot shape and size as homozygous chicks, the only different will be that Homozygous chiks are paler in color(dark grey) and Heterozygous chicks are pitch black.

Why the difference between Heterozygous barred males (B/b+) and Hemizygous barred females(B/-)? I suspect that it has to do with male vs female hormone levels at skin level, I suspect that Henny Feathering Barred males will look just like females but have not been able to find chicks of such genetics

 

[NatJ]

Why the difference between Heterozygous barred males (B/b+) and Hemizygous barred females(B/-)? I suspect that it has to do with male vs female hormone levels at skin level, I suspect that Henny Feathering Barred males will look just like females but have not been able to find chicks of such genetics

I suppose that makes sense. If you ever do find henny feathered barred chicks, I will be interested in seeing how/if that works.

 

[The Moonshiner]

You've lost me because in the past I hatched quite a few single barred male and barred female leghorns and they look identical at hatch all the way to adulthood as far as head spots and barring.
Maybe it has to do with my breed being fast feathering Idk.

 

[The Moonshiner]

And so that would mean with your stellar eye site that a double barred male over nonbarred hens would produce sex links for you?

 

[nicalandia]

And so that would mean with your stellar eye site that a double barred male over nonbarred hens would produce sex links for you?

No Sex links, but Sex influenced for sure. At least based on Extended Black and the type of barring found in Barred Rocks, studies have shown that Barred Rocks can be sexed Reliably 90% of the time by using the headspot alone without any other factors(down color, shank color), as is the case of the OP.