Not sure if I missed it, but another factor might be AMR. (Anti-microbial resistance is a mechanism for factory farming leading to pandemics, which you mention. But AMR causes other harms too)
From Carrique-Mas 2020, “the greatest quantities of antimicrobials (in decreasing order) were used in pigs (41.7% of total use), humans (28.3%), aquaculture (21.9%) and chickens (4.8%). Combined AMU in other species accounted for < 1.5%”.
Boeckel 2015 projects that “antimicrobial consumption [in livestock production] will rise by 67% by 2030 [relative to 2010]”.
Not sure if I missed it, but another factor might be AMR. (Anti-microbial resistance is a mechanism for factory farming leading to pandemics, which you mention. But AMR causes other harms too)
Thanks! I have now added: