Landrace/adaptive breeding discussion

[LaurenRitz]

In plant breeding, sometimes all that is needed is a cross between two inbred lines to bring things back into balance.

 

[Shadrach]

When I started in Catalonia I get told none of the hens would go broody. By the time I left every hen went broody; even those that didn't lay eggs.

I got told exactly the same at the field where I am now; the hens won't go broody. Now there are two broody hens out of three.

 

[fluffycrow]

When I started in Catalonia I get told none of the hens would go broody. By the time I left every hen went broody; even those that didn't lay eggs.

I got told exactly the same at the field where I am now; the hens won't go broody. Now there are two broody hens out of three.

Seems like you need to tell us your secrets

 

[Ridgerunner]

A lot of great discussion on here, I'm enjoying it.

Well there goes my (faulty) theory! I guess Cruella will stay in her pen..

If you try you might succeed. If you don't try you will not for sure.

My thoughts are that there are many different factors involved. I don't know how important any of them are or which might be causal or a consequence of something else. I suspect you would get different opinions from different genetics experts.

An observation that may mean nothing. When I started my flock I got a few hens of Delaware, Sussex, Orpington, and Australorp. I kept a Speckled Sussex rooster for what that's worth. All from Cackle hatchery, so hatchery chickens. I culled them down to 2 hens of each. When I culled down to those two of each breed I noticed that the Australorp had more of a fat pad than any of the others. When I eventually butchered those two Australorp they both had a huge fat pad. Out of those hens the two Australorp both went broody. After two and a half years none of the other ones did.

 

[U_Stormcrow]

And yet, many of those congenital diseases are recessives, reinforced by the extreme genetic bottlenecks in our racial history.

Chickens have a similar genetic bottleneck, or several, and we have far more flexibility with chickens.

Alternatively, they provide an evolutionary benefit **in some specific environments**, i.e. both Anemia and Thalassemia Minor providing some protection against Malaria infection.

I've even seen argument for an environmental factor favoring OCD in a small % of ancient hunters (not saying I agreed with the premise, or convinced by the paper, simply that I've seen a published article positing the theory in a reasonably regarded scientific literary magazine.)

 

[U_Stormcrow]

If you try you might succeed. If you don't try you will not for sure.

You miss 100% of the shots you don't take? the swings you don't make? similar quote by Bruce Lee for marital arts, etc...

 

[U_Stormcrow]

So we can assume that it's rather easy to bring back the "switch" by crossing to a broody line, especially since it's an evolutionarily "faulty" gene

Chickens have surprisingly complicated genetics when it comes to egg laying and associated behavior. The color genes obviously have some associated benefit in nature at making eggs less vulnerable to predation. Rates of fat deposit to support broody hens while unable to forage effectively, egg size and rate of lay (influenced by what local conditions can support over long time scale).

Man has spent the last few centuries aggressively selecting for birds that ignore many of the old constraints imposed by the environment, and centuries before that domesticating birds to at least partial human support. I don't doubt that those selections can be undone - look at how fast Cx offspring loose the fast growth and huge size traits - but reversing those selections is a far taller hill to climb.

I'm hoping more for a reversion to mean in my own landrace project - giving up egg production for some increased size, trying to preserve the rates at which the birds achieve sexual maturity. But not expecting RIR-like production or "Ranger"/Slow Broiler type size.

 

[Shadrach]

Seems like you need to tell us your secrets

The first secret is don't bother looking for a genetic explanation or wading through pages of studies.
Seriously, we don't know much about chickens despite centuries of of chicken keeping. The whole genetics completely determines behaviour is just plain wrong. It's not that genes don't play their role but there is a balance in there somewhere between environment and genes.

 

[Ridgerunner]

The first secret is don't bother looking for a genetic explanation or wading through pages of studies.

The group on this thread can't resist looking for explanations. It's just who we are. I agree with you. We can theorize all we want but that is just theory. What counts is what happens in the flock. (And I noticed the smiley face)

Seriously, we don't know much about chickens despite centuries of of chicken keeping. The whole genetics completely determines behaviour is just plain wrong. It's not that genes don't play their role but there is a balance in there somewhere between environment and genes.

I thought I mentioned this earlier, maybe in a different thread. I don't know how much is genetic and how much is environmental. I'm convinced it is both.

When I was fooling with this in my flock the easiest variable I could control was in selecting which chickens got to produce offspring. I elected to breed chickens that hatched from eggs laid by a broody hen, male and female offspring. They were typically hatched in an incubator and raised in a brooder, thought the brooder was in the flock. After a while I had a flock where every hen went broody.

That's one flock, hardly a scientifically significant number. But it is the best I can do.

 

[Perris]

The whole genetics completely determines behaviour is just plain wrong.

I don't know if you know it but that is the central message of Ball's How Life Works: a user's guide to the new biology 2023. It's heavy going, and I'm only up to chapter 5, but the idea of the genome as a blueprint is clearly defunct in current biological research.