Setting aside arthropods for a moment, I worry about the idea that switching to slower-growing breeds of broilers could lead to an increase in the total number of broiler-years endured in factory farm conditions (just because they might live for 70 days each rather than 40).
I estimate broilers in a reformed scenario grow 79.5 % as fast, which makes the cost-effectiveness of broiler welfare reforms 79.5 % of what it would be if they did not affect broilers’ growth rate, and resulted in the same increase in welfare per broiler-year. The implied increase in the number of broilers of 25.8 % (= 1⁄0.795 − 1) is much smaller than my estimate for the increase in the welfare per broiler-year of 92.9 %. So I think there is very little risk of broiler welfare reforms being harmful to chickens. My estimate for the increase in the welfare per broiler-year is also close to 100 %, which illustrates my assumptions imply broilers in a reformed scenario have lives which are close to neutral.
I tend to think of it like this: broiler and cage-free campaigns are not really aiming to change methods of production while holding fixed the amounts produced. They’re aiming for a reduction in the size of the industry, at least compared with what it would have been otherwise, due to growing consumer concern about the way the cheapest products on the market are produced.
This way of thinking about it reduces your particular concern while raising others. It now assumes lives in factory farm conditions are not worth living overall, and it assumes these campaigns are cost-effective ways of counterfactually reducing meat consumption. I hope they are, at least in some countries, but it’s hard to tell.
I believe the vast majority of the benefits to chickens of chicken welfare reforms come from improving the conditions of chickens, not from decreasing their consumption. I estimated in the post cage-free reforms decrease the consumption of eggs by “5.40 %”, which is much less than my estimate for the increase in the welfare per hen-year of80.4 %. I also think chickens in improved conditions have lives which are close to neutral, such that decreasing the population of chickens which have undergone a 2nd wave of welfare reforms may be harmful to chickens (although I think the overall effects would be unclear due to uncertain dominant effects on wild arthropods).
Thanks for the comment, Jonathan!
I estimate broilers in a reformed scenario grow 79.5 % as fast, which makes the cost-effectiveness of broiler welfare reforms 79.5 % of what it would be if they did not affect broilers’ growth rate, and resulted in the same increase in welfare per broiler-year. The implied increase in the number of broilers of 25.8 % (= 1⁄0.795 − 1) is much smaller than my estimate for the increase in the welfare per broiler-year of 92.9 %. So I think there is very little risk of broiler welfare reforms being harmful to chickens. My estimate for the increase in the welfare per broiler-year is also close to 100 %, which illustrates my assumptions imply broilers in a reformed scenario have lives which are close to neutral.
I believe the vast majority of the benefits to chickens of chicken welfare reforms come from improving the conditions of chickens, not from decreasing their consumption. I estimated in the post cage-free reforms decrease the consumption of eggs by “5.40 %”, which is much less than my estimate for the increase in the welfare per hen-year of 80.4 %. I also think chickens in improved conditions have lives which are close to neutral, such that decreasing the population of chickens which have undergone a 2nd wave of welfare reforms may be harmful to chickens (although I think the overall effects would be unclear due to uncertain dominant effects on wild arthropods).