I've yet to see any studies on the subject so I wouldn't be so quick to make such a statement. Mammals often pass down immunity to some extent through breast milk as well as through eating the mother's feces as in Koalas
That is true but let me clarify what I meant because I wasn’t clear. Acquired immunity, as in vaccination or exposure to a less lethal strain isn’t
genetically hereditary.
In the case of a mammal a mother can pass on antibodies to her offspring in utero or through milk, however that’s not genetic, future generations won’t inherit a genetic predisposition to resist a pathogen unless that genetic predisposition already exists, hence why a dog still needs to be vaccinated for rabies even if it’s parents were vaccinated.
Now there is epigenetics though and that is actually hereditary, viruses do attach their rna to host species sometimes which could give an individual some resistance theoretically, but a genetic researcher would be a better person to ask about that, definitely not me. As it is though if epigenetics do play a role with that they can’t anticipate new mutations and they seem unreliably random in their protection, hence the same viruses more or less are still being passed around and causing problems.
Good immune system genetics are hereditary however
I believe that "genetic quirk" is simply healthy genetics as shaped through the process of natural selection
Natural selection will solve the issue just as it's done for countless billions of years. Even with chickens, they've been traded around the world for the past 10,000 years and their immune systems have done an excellent job so far
Just take a look at the Egyptian Fayoumi for example. Indians traded Sri Lankan junglefowl along the Silk Road that made a journal of thousands of miles to another continent through the heart of many different ancient civilizations, and
Good immune system genetics are hereditary. I agree 100%. “Good” though is kind of the wrong word, “effective” is probably more appropriate because genetics that makes cells effective at resisting a virus can make it more susceptible to another virus and having a strong immune response isn’t always a good thing, the issue with chickens in general is their immune response to HPAI is too strong and that’s their downfall, very similar to COVID in some of us.
Natural selection and genetic diversity are the definite key to adapting to a world with hpai. Part of the issue with chickens is that most of the factory farms are mass populated with the same few breeds, it’s such a small genetic pool there isn’t much ability to adapt. Mixed backyard flocks may be more at risk from being exposed to bird flu but they have a better chance at adapting because they’re more likely to be mixed breeds and mixes of many different breeds.
As you said chickens have been brought around the world and have thrived because of natural selection and they’ve encountered and survived all sorts of different pathogens thanks to that, the context though here in particular is HPAI which in general chickens and other species are really struggling with.
HPAI and LPAI are basically the same species of virus currently, there are other versions of bird flu out there and have always been but mostly it’s been different flavors of H5N1 circulating lately, which shows how just small changes in it’s own dna have vastly different results, and that’s where the doom or salvation of or avian friends is.
Current HPAI is temporary. Viruses that adapt quickly tend to get milder over time because the virus better adapts to keeping itself alive through natural selection also. If a host dies quickly through an extreme immune response so dies the virus, eventually the milder ones proliferate better.
The problem with current HPAI is it is so nasty among chickens and other species that it has a chance of creating a bottleneck in chickens which is going to reduce genetic variability and their chances of adapting to future mutations. HPAI is also pretty much everywhere now and has many more opportunities to turn into new versions, better and worse. Next year or in a few years it may mutate into a benign version that becomes the next most dominant strain “hopefully” and after that it could get replaced again with something more lethal that chickens and other species have less resilience too once again, it could be a situation where the chickens that were wiped out by current HPAI may have had a genetic predisposition that may have made them resilient to the future lethal strain but because they’re gone the species as a whole is doomed to extinction.
This is obviously a worst possible case scenario that won’t likely happen, I’m just highlighting that genetic diversity is definitely important as you said and so might be other factors like vaccination “in my opinion” to stay ahead of this.
