I think there is some validity in what you are saying, but many points you raised (I can speak for myself) happens within a breeder's flock. What "nature" does for a land race "breed", I do for my flock. Instead of nature being the pressure, I am. If I apply pressure to a point where I only retain the fittest examples, then over time I have a flock more tolerant of my environment. But in addition to health and vigor, I have the opportunity to select good typed animals that are productive.
I think I see the cause of the confusion here... I'm not talking about landraces, but I think that's the impression you've gotten when I refer to mongrels. (?).
These mongrels I'm talking about are far more 'interfered with' or shaped by artificial/human pressures than a landrace is. They're usually also selected for productivity, but asides from that there's very little selection done, and often a whole lot of neglect. But not always.
Some owners of course don't select for or against anything. Not all mongrels are worthwhile, for sure.
Nevertheless they remain overall pretty productive because in the case of most mongrel flocks, they're not too far removed from productive types, and contrary to what some seem to believe, all those years of genetic selection for productivity does not just come out in the wash.
In some modern breeds, according to the poultry industry publications and sites I've seen, over half the spectrum of ancestral genes of the species have been lost through intensive selection for productivity. Letting most modern productive breeds 'mongrelize' can't cause reversion to a wild type that has been eradicated from their genetic inheritance.
I hear many theories of such from purebred breeders, saying things like "they will rapidly descend to a mediocre average", (referencing the wild or ancestral type returning in mongrel flocks) but I don't see it, and I don't hear mongrel breeders complaining of it, and certainly it's not happened in my flock, nor among any of the flocks that contained ancestors of my flock. From what I've seen, natural selection for wild type color returns fairly quickly in mongrel flocks, as well as feed efficiency, hardiness, and instinct levels, but that's about it as far as the 'inevitable return to mediocrity' goes... And even then, the 'wild-type coloring' shows because it's a deliberately retained phenotype, not really associated with true 'wild type' genotype. They remain fair to good layers and decently meaty birds, overall.
As far as I understand, given enough generations as a landrace, they would indeed manage, limited genepool or not, epigenetically etc, to return to the form that most suits them. But most mongrels are not being allowed to make a landrace of themselves, though they do have access to some pressures and aspects of that lifestyle as compared to the average purebred.
Another point that I would add is that just because a flock of "wild mongrels" are surviving, does not make them necessarily more resistant. I am going to use the Key West chickens as an example. Obviously they are surviving. They have adapted and are continuing to adapt to their environment. They also are not withstanding heavy exposure. They are being exposed, but the level of that exposure is relevant. Those same bird's offspring in close confinement would likely be just as susceptible as a "pure breed" that has been carefully selected on the same Island.
Again, this is referring to landraces, whereas I'm referring to mongrels people keep but neglect. They are not 'wild mongrels'; they're domestic animals of mixed ancestry, kept for agricultural purposes usually, but sometimes just as ornaments.
Obviously I'm not speaking for all mongrel-keepers but so far, every single mongrel owner I've gotten chooks from has repeatedly exposed them to numerous new birds from numerous other places, even very distant places. They have been heavily cross infected/exposed etc.
At no point would I consider an isolated landrace population on an island to be resistant to the same strains mainland animals are exposed to. They can be resistant to strains of them, but generally it's rather outdated resistance; with the rapid adaption of strains of disease constantly occurring, they would be susceptible if exposed.
Concerning the trade of mongrels. Is there a trade in mongrels?
Of course. Always has been, always will be.
What I have seen is mixed breeds being traded within a given area where the pressures are more or less uniform.
That's generally true especially when referring to custom mixes, i.e boutique crossbreds developed for a given purpose and usually sold within the limits of a certain geographical radius around each hatchery with a predetermined cull-by date practically emblazoned on their genetics, timed to deteriorate into premature graves within a few years if not culled sooner. Those mix/cross-breds don't contribute too much to resistance breeding, obviously. They don't go far, usually, but that said it's not too uncommon to ship even mix-breds across the country here.
I am not aware of mongrels being shared cross country, and if they are, it is a recent occurrence.
I live in Australia, not the US, lol. It's not a recent occurrence here, we've got chooks from all over Australia being traded and traveled and sold quite regularly; also, from what I've read of the history of the US, mongrels were also traded and sold and traveled long distances as well. Only in more built up areas has this not been so common. People being able to get the chooks they want from nearby breeders is a semi-recent development, which helped slow trade in mongrels, from what I've read.
Still, homebound mongrel flocks are always being exposed to the outside world via new chooks being brought in somewhat regularly, or the owners mingling with other people who also have poultry. The flocks most likely to operate in bubbles are either purebreds whose owners practice biosecurity, and remote landraces. There's always been fixed-location breeders, and customers who order birds from long distances, as well as those breeders and customers which like myself travel birds whenever they move rather than dump the whole flock and restart at the new location. Nothing new there, in fact it's just gotten so much easier to do it in this era.
In Australia, poultry imports were closed early on, and have remained stingy ever since; when people want quality birds in Australia they travel them across the whole country if needs be. Going by this forum and USA hatchery websites, it's commonly done in the USA too, and even if that's not mongrels being traveled, that's still birds which are pretty often carrying diseases being transported long distances, bringing new strains of disease to resident populations.
I am not certain what you mean by all over.There is haphazard trading of birds in my area. Usually it is hatchery stock, and sometimes they are mixed hatchery stock. They are not anymore resistant to disease (as a whole) than any other. The owners usually have more problems with disease, but the problem is usually rooted in the management of these birds.
I don't know what it's like in your area, I was referring to my area. And no, I agree, I don't find hatchery stock resistant to anything much. But they can serve as useful vectors of infection. I think also a distinction between 'mixed' and 'mongrel' is necessary; for example a 4-way crossbred and a mongrel are not the same thing in my usage of the term. Not sure what intended usage it has in your context.
I think your point is valid when you compare extremes. The land raced breeds of tropical Africa are better suited for their environment, than mine would be. Mine are originally from Peru by the way. Still if those land raced birds, if bred to fix type and color, would be no more or less resistant because they were. They would only become more or less resistant if the breeder used birds that were susceptible or more resilient. They are only removed from the gene pool if they die. If they succumb and recover they breed, and if they are resistant they breed. A breeder has the opportunity to remove a susceptible bird from the gene pool. A breeder has the opportunity to make faster progress on this one point because he/she has control over specifics.
I think there's been some misunderstanding of what I meant here. When I referred to mongrels, you appear to have substituted the word 'landrace' instead; I assume landrace and mongrel are synonymous to you, (just judging by your usage of it in response to my previous comments about mongrels), but they are distinct terms to me. Landraces are not managed by people, whereas even neglected mongrels are almost without exception still 'managed' by people, just in an often very slack-handed way.
The points you used with asserting that mongrel flocks would be more resistant could be used for pure breeds to. Some yes and some no. Many do not treat, trade their birds across country, and expose them too many birds at the shows etc. Some of course, do treat their birds and coddle them along. The variation is in the variety of breeders, as much as there is variation within breeds and strains.
Yes, there sure is a variety. In my experience though the breeders of purebreds are often carrying the really weakly birds, whereas those from mongrel breeders don't seem anywhere near so susceptible to anything. But I know this experience does not cover the whole spectrum, only mine; it's pretty hard to define what you mean when you're talking about mongrels in general, though, and those who breed them. You and I seem to have very different experiences of the subject matter and as you say there is a variety.
I think it's significantly different in Australia... We rely on long distance transport in ways some other more densely populated and habitable countries have almost forgotten about. It's not considered a big thing to go driving from one end of Australia to another just to pick up a car one has bought, for example, by most people I know. Most of us aren't so sedentary-minded when it comes to traveling that we'd balk at massive roadtrips for apparently small reward... After all that's kind of par for the course when you live in Australia, especially in rural areas, which is where my experience is based.
Our chooks get around almost as much as we do. I've lost count of how many times I've traveled my chooks now, lol, and how far. We've also traveled other animals all around Australia multiple times. I've known people who literally travel with chooks in their caravans, among other animals. Not saying it's necessarily ideal nor advisable (and probably not even legal) to do any of that, but it's just not considered really 'out there' and strange or anything like that.
(For the record the caravan chooks etc were all in quite decent health, allowed out at every stop, and no, their owners weren't the 'sort' of people who match probably the first dozen stereotypes that may spring to mind for some when considering what sort of character keeps chickens in a caravan while traveling around Australia).
I never intended to say that we could not or should not breed for resistance. I prefer to call it breeding for health and vigor because I want to be realistic with my expectations.
Well, perhaps that's a point of disagreement there. After all this thread is devoted to breeding for resistance and it is indeed a realistic expectation. The very 'health and vigor' you're breeding for is based on resistance to everything that opposes health.
Seems to me that it's a conflict of terminology rather than philosophy.
Best wishes.
