Recessive Cuckoo/Barred genes?

[Skyeknight]

This will be my first post on the forum, so my apologies if my format/storytelling is wrong or I make mistakes. So a few months I started doing a deep dive into the genetics of my flock, since I always just bred with random roosters I got and never kept track of heritage. At this moment in time I only have 2 hens left. The oldest is a semi-crested splash hen without any black feathers (first picture) and the second is a semi-crested blue hen with a cuckoo/barred patterned neck (second picture). This post is mainly about the genetics of the second hen. During the rabbit hole of genetics I learned that the cuckoo/barred gene is on the Z chromosome and dominant. But in my flock it seems to be recessive.

A little background on my flock. Early 2010s I got 2 eggs to hatch from a friend. These both became blue hens (third picture, no idea what breed). I bred these to a polish/Dutch crested splash coloured rooster. This resulted in a blue semi-crested hen. To this day I believe this to be the sole half-polish I had and therefore the common ancestor of all my semi-crested chickens. After this point I have no idea how all my chickens were related. I had 2 roosters with a cuckoo/barred phenotype bred from my own flock, I believe them to be father (fourth picture) and son (fifth picture). I believe one of these to be the father of my current living blue hen with the cuckoo/barred neck. The thing is that I didn’t know where the cuckoo/barred pattern came from. I never got a rooster from someone else with that pattern and its supposed to be dominant. Furthermore, I didn’t understand why my current blue hen only has a cuckoo/barred neck if its dominant. After realising that my current hen is proof that it isn’t so dominant that it would always show and therefore could be carried, I called my friend I got the eggs from way back if he happened to have a cuckoo/barred rooster around that time. He told me they did, but sadly didn’t have pictures. So now I assume at least one of those 2 blue hens carried the gene and just didn’t show it. But if one of them did then why didn’t that/those hen(s) show the same cuckoo/barred neck as my current hen?

So to summarize the questions I have:
- How can my hen in the second picture have a cuckoo/barred neck if that pattern is dominant?
- If the cuckoo/barred pattern can be co-dominant then why didn’t it show in my first 2 hens?

First picture, semi-crested splash hen.

Second picture, semi-crested blue hen with a cuckoo patterned neck.

Third picture, original 2 blue hens.

Fourth picture, small-crested cuckoo/barred father.

Fifth picture, small-crested cuckoo/barred son.

 

[HonkABC]

@nicalandia

 

[Amer]

Barring doesn't show up well on blue and splash birds, it gets blurred and almost erased. This is because of how the blue gene clumps pigment.
That's why only your hen's neck is clearly barred, with the blue gene, the neck will be more black while the rest of the bird is more blue (this is due to the feather structure.)
Meanwhile, white birds can have the gene without you ever knowing, since the barring gene causes white lines, how would you ever see the barring if the bird has no pigment?

 

[Skyeknight]

Barring doesn't show up well on blue and splash birds, it gets blurred and almost erased. This is because of how the blue gene clumps pigment.
That's why only your hen's neck is clearly barred, with the blue gene, the neck will be more black while the rest of the bird is more blue (this is due to the feather structure.)
Meanwhile, white birds can have the gene without you ever knowing, since the barring gene causes white lines, how would you ever see the barring if the bird has no pigment?

Sorry for the confusion but I guess the splash chicken is kinda irrelevant in this case. This answer just kinda raises more questions for me. Cause blue cuckoo with stripes over the whole body also exists. Can I just kinda see my hen as one of the possible phenotypes for blue cuckoo? Does this mean that my hens in the third picture are actually cuckoo too but just don't show it? how does the clumping together of pigment work? like why do some hens have stripes all over their body and others none at all?

 

[Amer]

Can I just kinda see my hen as one of the possible phenotypes for blue cuckoo?

Yes
The original blue hens were not cuckoo, the splash Polish was. Because it is sexlinked, the crested blue who is the origin of all your crested birds HAD to get it from her father.
Since he is splash (two copies of blue) it would be even harder to see any signs of barring.
Black chickens distribute eumelanin evenly over their feathers, however, blue chickens can't distribute it evenly and make microscopic "islands" of pigment. To the naked eye this looks solid grey but on the microscopic level it's clumps of black on a white background (like ink on a comic strip)

The barring mutation turns pigment production on and off. The clumping interferes with the barring.

 

[Skyeknight]

Yes
The original blue hens were not cuckoo, the splash Polish was. Because it is sexlinked, the crested blue who is the origin of all your crested birds HAD to get it from her father.
Since he is splash (two copies of blue) it would be even harder to see any signs of barring.
Black chickens distribute eumelanin evenly over their feathers, however, blue chickens can't distribute it evenly and make microscopic "islands" of pigment. To the naked eye this looks solid grey but on the microscopic level it's clumps of black on a white background (like ink on a comic strip)
View attachment 4022839
The barring mutation turns pigment production on and off. The clumping interferes with the barring.

Please let me know if I am coming to the right conclusion. Fully striped cuckoo hens would be fully black if they didn't have the cuckoo gene. Blue hens with the cuckoo gene are only in certain body parts striped because the different feather structures causes the clumpiness of the colours to act differently.

Adding pictures of the splash polish and his daughter the original crested blue hen for relevance.
Sixth picture, Splash polish rooster.

Seventh picture, original crested blue hen. Daughter of the polish rooster (I also believe her to be the mother of my current crested blue hen with the cuckoo neck, mainly because of the size of their crests).

The thing I don't understand now is why she didn't have any visible cuckoo traits like my current hen.

 

[Amer]

Please let me know if I am coming to the right conclusion. Fully striped cuckoo hens would be fully black if they didn't have the cuckoo gene. Blue hens with the cuckoo gene are only in certain body parts striped because the different feather structures causes the clumpiness of the colours to act differently.

Adding pictures of the splash polish and his daughter the original crested blue hen for relevance.
Sixth picture, Splash polish rooster.
View attachment 4023134

Seventh picture, original crested blue hen. Daughter of the polish rooster (I also believe her to be the mother of my current crested blue hen with the cuckoo neck, mainly because of the size of their crests).
View attachment 4023140
The thing I don't understand now is why she didn't have any visible cuckoo traits like my current hen.

Barring doesn't show up well on splash
https://www.backyardchickens.com/threads/barred-splash-splash-barred.1628702/
Your splash male probably had only one copy of barring, and his daughter inherited the non-barred allele from him.
Your current hen HAD to inherit her barring from her father since it is a sexlinked gene, hens do not pass it on to their daughters.

 

[Amer]

Who was the father of your cuckoo males? Because to me it looks like the splash Polish.

 

[Skyeknight]

Thank you for the link to the other thread, its helps a lot with understanding the cuckoo gene visually! Wish I had cleared pictures of my polish rooster for definitive confirmation.

I do not actually know who the father of my oldest cuckoo rooster is (fourth picture). I do not believe it to be the polish because of the very small crest and the single comb. This signals to me that he is a few generations removed from the polish. I have had a dark grey/blackish rooster that I believe to be a son of the original blue crested hen.

Are there any brown or white roosters with blackish patterns that could carry the cuckoo gene without it being obvious? Like columbia for example? Could I have gotten a Columbia rooster from someone that carried it? I know that partridge does combine with cuckoo and shows it more clearly.