Zoonotic diseases require frequent contact with large amounts of animals with large amounts of workers to have enough opportunity to make the difficult cross-species jump, so yes, factory farming is 100% the problem and giving both the animals and the people caring for them more space and making sure the workers have the time to do things right would make a huge difference. You're making a reducto ad absurdum argument by intentionally using absurd quantities and time periods that are not required to accomplish this goal.

I'm no vegan by far, but I'll definitely grant them that the modern animal product industry is unsustainable on numerous levels. Also whether or not humans are "meant" to eat meat, we're definitely not supposed to eat this much. There are aspects of other agriculture that are similarly so, however. A good example is produce such as avocados and citrus fruits that require a tropical climate but that spoil relatively easily meaning they have to be quickly transported to other areas to be consumed. They should be a relatively rarely eaten delicacy in places they don't normally grow, not something you can just pick out of a giant pile at the supermarket.

Plastics in general are another great example. You can't make a biodegradable anything that does what plastic does because not being biodegradable is exactly what makes plastics so useful to the modern lifestyle. They mean you can package something in a way that will stay sealed and fresh through all kinds of temperature and humidity changes when especially moisture is exactly what you need a biodegradable material to respond to. Plastics mean you can get exactly the flavor of doritos you're craving from the gas station at 2am. Plastics = convenience and that's the one thing that will be the hardest for all of us to give up.

Saving the planet and treating other humans better is just going to require a radical change in (particularly) western culture where we're used to just getting whatever we want whenever we want, and while the rich are certainly the most egregious offenders, one of the biggest ways they've suckered the rest of us into going along with it is by getting us addicted to small-scale versions of their unsustainable consumption habits.

• Unlike the similarly awful 2014 outbreak, you correctly point out that these outbreaks are originating in the wild. And keeping chickens in awful, inhumane conditions where they live in their own filth jam-packed among thousands of other chickens is basically the perfect vector for a pathogen.
• Getting chickens out of factory farms is a good unto itself, but I doubt you've ever watched any footage or done any research to familiarize yourself with the sorts of horrors you pay for when you buy eggs from a factory farm. Let alone based on your callous attitude that you would actually care about those horrors.
• Weird strawman that the two kinds of farms that exist are late stage capitalist hellholes where billions of chickens go every year to live a life of unfathomable torture... and your Aunt Betty's backyard chicken coop where every chicken gets a wacky name and their own posts on Facebook documenting their antics.

My mother raises hens and a dozen birds can actually make so many eggs that our entire family has trouble using them all. A bird lays on average one egg a day, and pasture-raised eggs are so rich as to be almost unpalatable to eat directly.

I don't think every farm needs to have some strict limit like that, but more numerous, smaller, more localized farms would be better for everyone in almost every way. Better environmentally, more humane to the birds, people get fresher and higher quality eggs, and more people are employed. Also more limited damage from diseases, droughts, and so on.

Our current system isnt just bad because "factories bad." It's bad because it's heavily centralized and top-down controlled. This is much cheaper to operate and funnels money towards the owner much better, but is so much worse in every way that local farms are better.

We're making millions of birds suffer and getting shittier, more expensive product because of it so less than a dozen people (the real bad eggs) can stay filthy rich.

On the other hand, I can get free range eggs cheaper than your factory made ones in the most expensive parts of the EU, and our population is greater than that of the US, we are feeding more people, yet I can safely eat them raw without the risk of salmonella.