New Report on the Welfare Differences Between Cage and Cage-Free Housing

In this post, “we” refers to Good Ventures and the Open Philanthropy Project, who work as partners.

Over the last two years, animal welfare organizations successfully secured pledges from major restaurants and grocers to eliminate battery cages from their supply chains, which are collectively expected to bring cage-free housing from ~13% of the domestic egg supply to ~70% when fully implemented. We have been the largest funder of these campaigns.

In our blog post announcing our support for these campaigns, we claimed that cage-free systems were much better than battery cages for hen welfare, based on initial research conducted by Lewis Bollard, our program officer for farm animal welfare. Lewis briefly argued against a memorandum by animal rights group Direct Action Everywhere (DxE) which claimed the opposite. This disagreement was further explored in a series of comments written by Lewis and Wayne Hsiung of DxE.

We left that discussion unsatisfied with our knowledge about the evidence on hen welfare in different housing systems, and I (Ajeya Cotra) conducted a more thorough investigation -- the full report can be found here. My findings were, in short:

In light of this new investigation, we believe we were overconfident in our unqualified initial statement that "Cage-free systems... [are] much better than cages." In particular, we had put substantial weight on a pre-existing quantitative assessment that ranked hen housing systems on a 0-10 welfare scale; we are now much more skeptical of that paper’s methodology. Additionally, we now think it is likely that mortality rates in aviaries will be higher than in cages in the years immediately after farmers transition to cage-free production, though we expect this initially-high mortality to decline significantly as farmers follow profit incentives to improve management practices and reduce mortality to roughly the levels currently seen in commercial cage-free farms in the US and the UK. We continue to believe our grants to accelerate the adoption of cage-free systems were net-beneficial for layer hens, but we feel we made a mistake by not conducting a more thorough review of the research on this topic earlier.

In addition, it seems clear to us that cage-free systems have much higher welfare potential than battery cage systems -- that is, the theoretical highest-welfare hen housing system would not contain cages. Though we stand by our bottom line, we appreciate the pushback from Direct Action Everywhere for prompting us to look more closely at the evidence base.

For more details, read the full report here.