Ongoing Brahma Projects Thread

[big medicine]

Was this an issue that just showed up in your flock or did you introduce it?

The reason I ask is because I have birds from a strain with nice hocks and some from another strain with the Cochin type feathering. I hope to keep the clean hocked strain pure but would also like to cross some with the second strain in hopes of getting some specific improvements for a future outcross.

If this was something that just showed up in your flock and was difficult to get rid of then I may not even try a cross.

It went all the way back to the first Cornish/ Cochin cross pullet that started the silver laced Brahma project many years ago. It took many, many, years to breed it out. Or so I thought. After no sign of it for a few generations I thought I had it eradicated. That was the year I had decided to release some hatching eggs via auction here on BYC. But it turned out that the male and at least one female in the breeding pen where still harboring a hidden single copy resulting in a few full blown vulture hocked chicks. Even worse was the fact that some of the folks who had gotten them were less than selective setting up their breeding pens, resulting in spreading the fault.

Being a recessive trait which requires a copy from each parent to show itself, I would not breed from any bird showing it, or their young. A full blown two copy bird will pass a single copy to all it's chicks regardless what it is breed to. This single copy bird will have normal looking hocks, but will pass the trait on to half it's chicks, and they to their"s, and so on, and so on.

 

[bumpercarr]

It went all the way back to the first Cornish/ Cochin cross pullet that started the silver laced Brahma project many years ago. It took many, many, years to breed it out. Or so I thought. After no sign of it for a few generations I thought I had it eradicated. That was the year I had decided to release some hatching eggs via auction here on BYC. But it turned out that the male and at least one female in the breeding pen where still harboring a hidden single copy resulting in a few full blown vulture hocked chicks. Even worse was the fact that some of the folks who had gotten them were less than selective setting up their breeding pens, resulting in spreading the fault.

Being a recessive trait which requires a copy from each parent to show itself, I would not breed from any bird showing it, or their young. A full blown two copy bird will pass a single copy to all it's chicks regardless what it is breed to. This single copy bird will have normal looking hocks, but will pass the trait on to half it's chicks, and they to their"s, and so on, and so on.

I think maybe Huntress was asking about the soft tweeners rather than full blown VHs. It really stinks that it got out of control like that.

I have a full scratch paper now after running about a million punnett squares, dihybrid and trihybrid. It's crazy. Let me see if I can explain what I'm seeing and maybe you can tell me where I'm going wrong. Unfortunately, I have to make a few assumptions. First, if the tweener hocks (wish I had a better word, but I don't) is caused by two genes and is recessive...aabb would show the tweeners, AABB, AaBb, AaBB, AABb would not. The only way to ensure that a bird didn't carry any of the three gene combos that could make it show up would be to breed them to an aabb bird and hatch them, knowing that all of them would carry some combination of the genes and would need to be culled. 25% of the chicks would have the tweeners. If it is caused by three genes, you would need to hatch twice as many as only 12.5% of the chicks would show the tweeners.

However, if you take a bird that does not show the tweeners and breed it to a bird that you are fairly certain does not carry the trait at all, 25% of the chicks will not carry the combo of the genes for the dihybrid cross (two genes) and 12.5% of the trihybrid (three genes). Of course, that is assuming the worst case scenario, where one of the parents carries one of each of the two or three genes that you are trying to eliminate. Because there are so many different combinations (4 for the dihybrid and 8 for the trihybrid), as the consequent generations are bred to a bird that is free of the tweener genes, the more diluted the genes become and the less likely that there will be a combination that will show the tweeners, but the genes will always be there in some combination. You will have eliminated the possibility of coming up with the tweeners by the second generation, again assuming that you are breeding to a clean bird and a bird that has only one of the two or three genes required (and that two or three genes are required, a single gene is a completely different story). Now if you breed this line back to itself again, you start increasing the likelihood of getting the genes back in the line....the further apart the generations are the less likely, but the likelihood is that it is still there.

I guess this is why some discourage the use of line breeding. As you breed father to daughter, mother to son, and siblings to each other it is too easy to bring back traits that you took the time to get rid of.

So, I suppose the safest practice is to not line breed which is probably impractical for most of us. Another option would be to keep a line that you are fairly certain doesn't contain the problem and then use that line to breed into the other line. But the record keeping involved would be pretty extensive as you get further down the road.

Still mulling all of this over, it is making my head hurt.

 

[bumpercarr]

It would be almost worth it to be able to get your chickens genetic map tested. LOL.

 

[Huntress78]

Quote:
Interesting. So do you think you've eliminated it in your own flock now?

You said "This single copy bird will have normal looking hocks, but will pass the trait on to half it's chicks"
So at this point in a breeding program one could take those chicks and do a VH test by breeding back to a two copy bird correct? If good records were kept you could then eliminate the carriers from the program.

If this assumption is correct then crossing some of my 'clean hocked' birds and the 'soft VH' birds this year would not only start a new line but also be a test to make sure the 'clean hocked' birds are not carriers.

 

[big medicine]

Well, the theory that you should always keep spare males around came into play today. I looked out toward the blue laced red group this afternoon and saw a bird down inside the fence. While getting dressed to go out in to the arctic I keep looking out the window for a hawk, on the ground, or in a nearby tree. Could not see one, or the loose feathers you would expect with a raptor kill.

When I get out there it is one of the two males I had in that pen. He is laying on his side, neck out stretched, with his beak kinda tucked against his neck. Not a mark on him, big, heavy, still warm and limp, slight purple tint to his face.

I did a quick necropsy, only thing I could see was an enlarged heart.

I was figuring on him playing a role in this years breeding pen. He had pretty good size and type, He is laying on a split fifty pound feed bag for perspective.

 

[bumpercarr]

Well, the theory that you should always keep spare males around came into play today. I looked out toward the blue laced red group this afternoon and saw a bird down inside the fence. While getting dressed to go out in to the arctic I keep looking out the window for a hawk, on the ground, or in a nearby tree. Could not see one, or the loose feathers you would expect with a raptor kill.

When I get out there it is one of the two males I had in that pen. He is laying on his side, neck out stretched, with his beak kinda tucked against his neck. Not a mark on him, big, heavy, still warm and limp, slight purple tint to his face.

I did a quick necropsy, only thing I could see was an enlarged heart.

I was figuring on him playing a role in this years breeding pen. He had pretty good size and type, He is laying on a split fifty pound feed bag for perspective.

Oh man. That really stinks. I lost one to unexplained reasons about a month ago. It's always the ones that you are planning on using too. He looks like he was a really nice size.

So sorry...........

 

[big medicine]

Interesting. So do you think you've eliminated it in your own flock now?

You said "This single copy bird will have normal looking hocks, but will pass the trait on to half it's chicks"
So at this point in a breeding program one could take those chicks and do a VH test by breeding back to a two copy bird correct? If good records were kept you could then eliminate the carriers from the program.

If this assumption is correct then crossing some of my 'clean hocked' birds and the 'soft VH' birds this year would not only start a new line but also be a test to make sure the 'clean hocked' birds are not carriers.

Sorry I had missed this.

Yes, breeding a suspected one copy bird to a known two copy bird should produce 50% two copy vulture hocked chicks.

On the last one, not so sure. They may be different genetics involved between the soft, versus hard feathered varieties. Worse case, you are producing a line with bunch of one copy birds. If it was me I would avoid using either form if at all possible.

 

[armansourani]

hey there.
i was thinking about the shape of the comb in the brahma.
some are Saw like some are flat and some are wulnut shaped.personally i prefer Flat form like my silver brhma rooster.so can anybody guide me how is the inheritance of comb appearance?
and how i can get flat combs out of wulnut/semi sw shaped parents?
i would be appreciated.

 

[big medicine]

hey there.
i was thinking about the shape of the comb in the brahma.
some are Saw like some are flat and some are wulnut shaped.personally i prefer Flat form like my silver brhma rooster.so can anybody guide me how is the inheritance of comb appearance?
and how i can get flat combs out of wulnut/semi sw shaped parents?
i would be appreciated.

A proper and correct Brahma comb is a small, tight, three ridged, pea comb. Variations from that usually indicates a outcross to other comb types in a birds family tree. My guess would be that the small flat combs you describe re a result of some rose comb influence. I know in my case bringing some Wyandotte blood into a Brahma project resulted in many variations of small low combs for a few years. In my case I bred to get back to a proper pea comb so I really can't say with certainty how to breed for these variations, other than to use the birds that most closely resemble what you want in your breeding pens.

Now the question may be, if you are breeding for a non pea comb, should you be calling them Brahmas ?

 

[armansourani]

A proper and correct Brahma comb is a small, tight, three ridged, pea comb. Variations from that usually indicates a outcross to other comb types in a birds family tree. My guess would be that the small flat combs you describe re a result of some rose comb influence. I know in my case bringing some Wyandotte blood into a Brahma project resulted in many variations of small low combs for a few years. In my case I bred to get back to a proper pea comb so I really can't say with certainty how to breed for these variations, other than to use the birds that most closely resemble what you want in your breeding pens.

Now the question may be, if you are breeding for a non pea comb, should you be calling them Brahmas ?

well.. i heard that Pea comb is a recessive allele with pure genotype e.g pp.but a wulnut shaped comb is heterogenous allele Pp and Saw like combs are Dominantly PP.
i dont know is that true or not.so no contraversy with pea comb.
well my main concern is about this my silver colombian has a pea comb but my golden one has a comb like this.


now i want to know 1- can we call this rooster a Brahma and second is that is there any way to get pea comb generation out of this man or not?
thanks.