Sex- linked Information

[junebuggena]

Crossbreeds usually grow faster and start laying earlier than either parent breed.

 

[Ridgerunner]

There is nothing magical in them being sex links. They are not going to lay better or grow faster because they are sex links. They are going to inherit traits from both parents. If both parents come from flocks that lay well, the offspring will probably lay well.

When you cross chickens that are inbred with another chicken that is from a different flock so it is not inbred the same way you can get something called hybrid vigor from the increased genetic diversity. It does not have to be chickens from a different breed, it just has to be a chicken that is not inbred the same way so new genetics are introduced to increase genetic diversity. Most sex links from hatcheries lay well for one of two reasons. Some are from the commercial egg laying hybrid crosses. These lay extremely well. The others come from two different flocks that both lay well so they inherit those good egg-laying genes plus they can get an additional boost from hybrid vigor.

But that is not because they are sex links. If you put a Rhode Island Red rooster over a Delaware hen (both hatchery stock) you will get a red sex link where the pullets probably lay really well. If you put a Delaware rooster over a RIR hen from those same flocks, you will get pullets that lay just as well. They lay well because of the cross of good genes and a boost from hybrid vigor, not because they are sex links.

 

[SunnySideUpGUAM]

Gotcha

 

[Melschen]

Wow! That is a ton of information. I know if I take a black copper marans roo over a cream legbar hen you should get a sex link. Would the opposite work as well? We have a cream legbar roo and marans, welsummer and wyandotte (gold, silver and BLR) pullets.

 

[junebuggena]

Wow! That is a ton of information.

I know if I take a black copper marans roo over a cream legbar hen you should get a sex link. Would the opposite work as well? We have a cream legbar roo and marans, welsummer and wyandotte (gold, silver and BLR) pullets.

It's the hen that is the important part of the equation for sexlinking. It does not work if you use a barred rooster or a silver rooster.

 

[triplepurpose]

It's the hen that is the important part of the equation for sexlinking. It does not work if you use a barred rooster or a silver rooster.

Right. A barred rooster will give barring to all his offspring, so a barred rooster over non barred hen just makes a bunch of chicks that all have one copy of the barring gene--ergo, not sex links. Whereas the female can only give barring to her sons.

ya know, I had read and had people explain this to me over and over but then the other day i finally puzzled it out piece by piece and fully visualized how it works: like a lightbulb coming on! dunno why it took me so long, when its really so elegantly simple--i like to think i am reasonably intelligent and i did study basic genetics in a bit highschool and elsewhere... but i guess its all rather abstract for most unless you figure out a way to visualize it schematically....

 

[dheltzel]

Right. A barred rooster will give barring to all his offspring, so a barred rooster over non barred hen just makes a bunch of chicks that all have one copy of the barring gene--ergo, not sex links. Whereas the female can only give barring to her sons.

ya know, I had read and had people explain this to me over and over but then the other day i finally puzzled it out piece by piece and fully visualized how it works: like a lightbulb coming on! dunno why it took me so long, when its really so elegantly simple--i like to think i am reasonably intelligent and i did study basic genetics in a bit highschool and elsewhere... but i guess its all rather abstract for most unless you figure out a way to visualize it schematically....

You are correct, assuming (as we usually do) that the barred rooster is homozygous for barring. In creating Welbars (a crele colored Welsummer) I had to breed from cockerels that were heterozygous for barring. I had full Welbar pullets a full generation before correct, homozygous barred cockerels appeared.

Heterozygous roosters produce half non-barred offspring when crossed to a non-barred pullet, but not of single sex, so it is useless for sexing chicks.

 

[triplepurpose]

You are correct, assuming (as we usually do) that the barred rooster is homozygous for barring. In creating Welbars (a crele colored Welsummer) I had to breed from cockerels that were heterozygous for barring. I had full Welbar pullets a full generation before correct, homozygous barred cockerels appeared.

Heterozygous roosters produce half non-barred offspring when crossed to a non-barred pullet, but not of single sex, so it is useless for sexing chicks.

If you dont mind my asking, why heterozygous roosters? Do you mean that was all you had to work with or that it was a deliberate choice? I understand how during the process of stabilizing or creating an autosexing breed based on barring like welbars one will have some heterozygous cockerels along the way before you get to a true-breeding and homozygous endpoint (as I understand it), but is there a specific advantage to starting with heterozygous cocks...? Or did I just misunderstand you...?

 

[junebuggena]

If you dont mind my asking, why heterozygous roosters? Do you mean that was all you had to work with or that it was a deliberate choice? I understand how during the process of stabilizing or creating an autosexing breed based on barring like welbars one will have some heterozygous cockerels along the way before you get to a true-breeding and homozygous endpoint (as I understand it), but is there a specific advantage to starting with heterozygous cocks...? Or did I just misunderstand you...?

F1 males would only have a single copy of the barring gene. You would not have homogenous males till the second generation, and getting one worth keeping to breed might not happen till F3.

 

[dheltzel]

If you dont mind my asking, why heterozygous roosters? Do you mean that was all you had to work with or that it was a deliberate choice? I understand how during the process of stabilizing or creating an autosexing breed based on barring like welbars one will have some heterozygous cockerels along the way before you get to a true-breeding and homozygous endpoint (as I understand it), but is there a specific advantage to starting with heterozygous cocks...? Or did I just misunderstand you...?

You are correct, I was creating Welbars from Welsummers and Barred Rocks. Before I had a double barred cockerel, I used a single barred cockerel over a barred pullet. Half the males were double barred, and (for the first time since starting the project) easily selected at hatch. But half the pullet chicks were un-barred and I had to raise them a few weeks to determine that. The unbarred pullets were sold as layers and the feedback I got was that they were great birds because the heterosis was still strong in that generation. They didn't quite look like Welsummers, but laid the same dark eggs.

That generation, when the double barred chicks appeared, was the first time I ever had true Welbars in my possession. I am on my 3rd generation since then and they are 100% true breeding and autosexing. Last summer, I put double barred cockerels over my entire flock of Welsummers to produce a lot of pullets. As a side effect, I had a lot of single barred cockerels, which I released on the farm to find their way in the world. Many have survived and they are incredibly beautiful birds. I need to get some pics. It's a shame they don't breed true because I think they are prettier than the double barred cocks, though that is really "in the eye of the beholder".

Anyway, even though the het roos are a genetic undesirable, they are still very nice birds. If you check out Greenfire Farm's FB page, they have posted a few Welbar pics as a teaser for their planned introduction this year. Every cockerel that have pics posted is clearly single barred, I think they find the single barred ones more attractive also. The pullet pics are correct, also single barred, but supposed to be so. I'm fairly certain they did the same thing I did last year and have a bunch of het cockerels running around their farm. Ever notice how the free ranging cocks look so nice compared to the ones in the breeding pens? I think the ones in the pens with the girls sort of "let themselves go", but the ones without a female are always preening -- like teenage boys