Fibro OE project

Nicks_Chicks

Songster
May 15, 2024
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The Cornhusker State
Hey, so I'm planning on breeding some fibro EEs my crossing my ayam cemani rooster with several colors of Ameraucana hens (and maybe some CCL). I also Fibro OEs. So I'm planning on taking the F1 FEEs( Fibro EEs) and crossing them to a marans rooster. Now, I know only 50% of the offspring will carry the blue egg gene, and I've also heard that the blue egg gene is linked to pea combs, and the chances of hatching a chick that carries both the blue egg gene and has a single comb (with the exception of using CCL) is only 3-4%. So when I breed the F1s to the marans, then I will only want to keep the chicks that hatch with a pea comb, and cull the ones with sing comb, correct?
 
I knew about the linkage but didn't know it was such a low chance for the pea combs and blue eggs to break linkage!
Yes, it's best to keep the chicks with a pea comb.
 
I've also heard that the blue egg gene is linked to pea combs, and the chances of hatching a chick that carries both the blue egg gene and has a single comb (with the exception of using CCL) is only 3-4%. So when I breed the F1s to the marans, then I will only want to keep the chicks that hatch with a pea comb, and cull the ones with sing comb, correct?
Yes, if your original chickens have the pea comb/blue egg linkage, you will want to keep the chicks with pea combs.

Of course the linkage can go any direction:
pea comb/blue egg (Ameraucana)
pea comb/not-blue egg (Brahma)
not-pea comb/blue egg (Cream Legbar)
not-pea comb/not-blue egg (most of the common brown-egg and white-egg types of chickens)

I have read there is about a 5% crossover rate. So yes, you can expect the pea comb (or not-pea comb) to stay linked with the blue egg gene (or not-blue egg gene), whichever way it was when you started, about 95% of the time.
 
In my project I chose to use the comb linkage for efficiency.
By only selecting pea comb birds it's improbable to get non-blue egg gene offspring.
If a hen has a broken link it will show up at pol, and if a roo is suspect DNA testing would help sort it out.
I intend to use the DNA testing further down the road to confirm homozygosity.

What seems to me more challenging is to keep Fibro in a project while performing multiple crosses.
I ended up with one, just one, keeper hen from my fibro mixes. She's great, but I had a white skinned roo, and then a barred roo, and neither will produce fibro. So her breeding has been on hold. Now that a slate roo has finally grown out, the fibro hen is on an egg laying break. lol

With crossing to marans, if barred, that would present the same problem. A barred hens sons will be barred and not show Fibro.

Anyway, for a multiple cross project, I decided on keeping a few lines, or "pens" (although currently juggling it in one flock with alternate roo timing now that things are more progressed). But at the start I had it set up with one-way crosses of everything, and then bred the siblings together or back to a parent to cement some of those genes before bringing them to the next mix.
So out of 7 breeds I now have 3 lines, soon to be 2. I envision it as an upside down pyramid, or a weaving project. Just trying to first get all the desired genes into this soup, and then later strain the soup to remove everything undesirable. Although a lot was easy to get rid of early on, other stuff can pop up as you go along.
 
I'm going in the other direction to see if I can get past the linkage. I really would like a straight combed blue egg layer that is not CCL. We shall see if I can do it in 20years. The calculator thinks I can.:lau
 
I'm going in the other direction to see if I can get past the linkage. I really would like a straight combed blue egg layer that is not CCL. We shall see if I can do it in 20years. The calculator thinks I can.:lau
Is there a reason not to start with a Cream Legbar and breed toward what you want?

I think McMurray's "Whiting True Greens" have single combs and the blue egg gene, so that would be another place you could get the linkage of blue egg and not-pea comb.
 

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