Re: your footnote: I think this depends heavily on how severe we are talking. I don’t have a strong opinion, because I really think no one has looked at it, about how much more severe things can get from disease than from something like keel bone fractures. A priori it doesn’t seem unreasonable to assume that the artificial conditions of factory farming enable a chicken to live in pain much longer, and therefore have higher overall suffering, than we would ever see in the wild—but I’m not that confident in that idea, so it would be good to look at more diseases. The point being that a severe enough disease could still be worth working on in dalys/​dollar terms even if it doesn’t affect that many individuals, and that would also make it more ecologically inert in many cases (since changing the circumstances of very large numbers of animals seems riskier).
WAI facilitated a grant from Coefficient (then OP) years ago to look at disease severity; they came out with a few papers recently here and here. As is perhaps unsurprising, but disappointing, much of the research on disease in wildlife doesn’t provide enough info to do a good job estimating the welfare burden. But the high scoring bacterial zoonoses in the first paper could be a good place to start a research project attempting to better assess the severity and numerosity compared to FAW conditions (as a cost effectiveness bar).
Re: your footnote: I think this depends heavily on how severe we are talking. I don’t have a strong opinion, because I really think no one has looked at it, about how much more severe things can get from disease than from something like keel bone fractures. A priori it doesn’t seem unreasonable to assume that the artificial conditions of factory farming enable a chicken to live in pain much longer, and therefore have higher overall suffering, than we would ever see in the wild—but I’m not that confident in that idea, so it would be good to look at more diseases. The point being that a severe enough disease could still be worth working on in dalys/​dollar terms even if it doesn’t affect that many individuals, and that would also make it more ecologically inert in many cases (since changing the circumstances of very large numbers of animals seems riskier).
WAI facilitated a grant from Coefficient (then OP) years ago to look at disease severity; they came out with a few papers recently here and here. As is perhaps unsurprising, but disappointing, much of the research on disease in wildlife doesn’t provide enough info to do a good job estimating the welfare burden. But the high scoring bacterial zoonoses in the first paper could be a good place to start a research project attempting to better assess the severity and numerosity compared to FAW conditions (as a cost effectiveness bar).