[ars]

No, that's simply not true. It's being spread by wild birds, not concentrated farming.

I know people love to blame "big anything", but it's just not true here.

Here's a source:

https://www.cdc.gov/bird-flu/virus-transmission/avian-in-bir...

"Domesticated birds (chickens, turkeys, ducks, etc.) may become infected with avian influenza A viruses through direct contact with infected waterfowl or other infected poultry, or through contact with surfaces that have been contaminated with the viruses."

[miltonlost]

"Domesticated chickens may become infected by wild waterfowl or by other infected poultry", and other infected poultry includes domesticated chickens. Nowhere in that web page does it say that domesticated chickens cannot spread it to other domesticated chickens. Once a domesticated chicken becomes infected (however it became infected) in a massive concentrated area, it will spread that infection to other domesticated chickens. You're conflating "spreading across chicken farms by flight" with "spreading within chicken farms by already infected chickens" and saying the first is true so therefore the second can be.

[ars]

I'm not conflating it. Spread with Avian flu means to other places. A single chicken in a farm means ALL chickens will get it. That's such a trivial thing, it's not even worth noting.

What matters is how does it spread.

I think what's confusing you is that there are diseases where a single infected animal does NOT mean all animals will get it, and in those cases the more concentrated the farm the higher percent of other animals will get it.

That exists. But it's not the case here. Here it's 100%, doesn't matter if it's a concentrated farm, or a pastoral farm with chickens walking in the house.