Thanks for this detailed presentation. I think it serves as a helpful, clear, and straightforward introduction to the models and uncovers aspects of the original model that might be unintuitive and open to question. I’ll note that the model was originally written by Laura Duffy and she has since left Rethink Priorities. I’ve reached out to her in case she wishes to jump in, but I’ll provide my own thoughts here.
1.) You note that we use different lifespan estimates for caged and cage-free hens from the welfare footprint. The reasons for this difference are explained here. However, you are right that though we attribute longer lives for caged hens – on the assumption that they are more often molted to extend productivity – we don’t adjust the hours-spent-suffering of caged hens, and that the diluted suffering of caged hens leads to a less effective verdict in the model.
I see three choices one could have made here: discard our lifespan assumptions, try to modify the welfare footprint hours-spent-suffering inputs, or keep the welfare footprint inputs paired with our longer lifespans. The final option is in some sense a more conservative choice and is the one we went with (but I can’t say whether it was an oversight or a deliberate choice).
Your alternative approach of using the welfare footprint numbers for both hours spent suffering and lifespan estimates seems sensible to me and would be less conservative.
2.) I believe some of the differences in your approach and ours may be explained by our desire to account for differences in productivity between hens in each environment. Our model includes estimates of eggs per chicken and assumes there need to be more cage-free hens to produce the same number of eggs. By lobbying for cage-free systems, you also increase the number of chickens confined in farms. This is accounted for in the variable Ratio CF/CC Hens, which we estimate to be 1.05. Including this further reduces the efficacy of cage-free campaigns because transitioning will increase the number of total hens.
Thanks for this detailed presentation. I think it serves as a helpful, clear, and straightforward introduction to the models and uncovers aspects of the original model that might be unintuitive and open to question. I’ll note that the model was originally written by Laura Duffy and she has since left Rethink Priorities. I’ve reached out to her in case she wishes to jump in, but I’ll provide my own thoughts here.
1.) You note that we use different lifespan estimates for caged and cage-free hens from the welfare footprint. The reasons for this difference are explained here. However, you are right that though we attribute longer lives for caged hens – on the assumption that they are more often molted to extend productivity – we don’t adjust the hours-spent-suffering of caged hens, and that the diluted suffering of caged hens leads to a less effective verdict in the model.
I see three choices one could have made here: discard our lifespan assumptions, try to modify the welfare footprint hours-spent-suffering inputs, or keep the welfare footprint inputs paired with our longer lifespans. The final option is in some sense a more conservative choice and is the one we went with (but I can’t say whether it was an oversight or a deliberate choice).
Your alternative approach of using the welfare footprint numbers for both hours spent suffering and lifespan estimates seems sensible to me and would be less conservative.
2.) I believe some of the differences in your approach and ours may be explained by our desire to account for differences in productivity between hens in each environment. Our model includes estimates of eggs per chicken and assumes there need to be more cage-free hens to produce the same number of eggs. By lobbying for cage-free systems, you also increase the number of chickens confined in farms. This is accounted for in the variable Ratio CF/CC Hens, which we estimate to be 1.05. Including this further reduces the efficacy of cage-free campaigns because transitioning will increase the number of total hens.