Summary

Using historical data from 2015-2024, The Humane League (THL) estimates that each dollar spent on cage-free corporate campaigns has spared approximately two hens from cages. This estimate covers both the acquisition of new corporate commitments and the accountability work required to ensure those commitments are fulfilled across THL’s US and Global corporate cage-free efforts.

The calculation draws on:

• Corporate cage-free policy fulfillment data collected by THL
• Estimates of the number of hens spared by each corporate policy THL helped secure
• Historical program cost data, adjusted for inflation and including proportional overhead

It is important to note that this is not an estimate of THL’s overall cost-effectiveness. Rather, this analysis covers only THL’s corporate cage-free campaigns. Other programs, such as THL’s movement building work via the Open Wing Alliance or broiler welfare, are excluded here. 

The goal of this analysis is twofold: to inform internal resource allocation, and to offer a transparent, accessible response to one of the most common questions asked by THL supporters. The methodology used prioritizes accessibility over granularity at some points, which are detailed in the “Additional Assumptions & Limitations” section. 

While this model is simplified, we are encouraged that the resulting estimate is within the bounds of independent evaluations by Animal Charity Evaluators (11 hens per dollar) and Saulius Šimčikas (12 to 160 chicken years per dollar) when we consider the key difference in our methodology. In contrast to other methodologies, THL does not find evidence supporting other evaluators’ assumptions that advocacy merely accelerates cage-free transitions that would occur eventually. We view advocacy as the decisive factor that makes such transitions happen. Consequently, our estimate is not multiplied by a number of years of suffering averted. This leads to a lower cost-effectiveness number than other analyses, because our model measures only the immediate impact of achieving change, rather than distributing that impact over a set number of years.

Methodology & Assumptions

Hens spared from a cage per dollar spent by THL = (Hens Impacted By Commitment x Fulfillment Rate x Credit Multiplier) ÷ (Cost Of Acquisition + Cost Of Accountability)

Hens Impacted By Commitment: The total estimated number of hens covered by corporate cage-free commitment policies that THL has worked on.

• THL has developed a detailed methodology to map corporate egg use at the sector and company level by leveraging available egg use data to extrapolate unknown companies’ egg use, and from that the number of hens in a company’s supply chain. These are order-of-magnitude estimates and should not be treated as overly precise. 
• The "Hens Impacted" number for each policy, regardless of the year it was secured, is calculated using THL’s most recent estimates. A company may increase or decrease the number of eggs they use over time, meaning we spare more or less hens than we say. Unfortunately, we don’t have data available for many prior years. Company-specific egg purchasing varies year to year and we expect that roughly offsets across the policies in scope; however, systemic changes in layer flock size over time could bias totals. 

Fulfillment Rate: The percentage of a company’s egg supply sourced from cage-free hens, verified to the best of our ability.

• The numbers come from direct company reporting, internal verification, research, and best estimation, and are current as of August, 2025. Collecting this data partway through 2025 allows for the calculation to include some, but not all, of the company reporting updates for 2024.
• Fulfillment data is complex. Some companies report interim progress, while others report nothing until the commitment is 100% met. Non-reporters are assumed at 0%, creating a downward bias.

Credit Multiplier: This multiplier adjusts our "Hens Impacted By Commitment" figure downward to account for the collaborative nature of the farm animal advocacy movement.

• We apply a 50% multiplier to the number of hens impacted. We decided to include a credit multiplier to account, in a very rough sense, for the collaborative nature of the farm animal advocacy movement, as well as external factors like state laws. For example, for a global policy, Open Wing Alliance members may have contributed to policy acquisition and/or fulfillment. We aimed to be conservative in accounting for THL’s contributions vs. the contributions of other organizations.
• The credit multiplier shouldn’t be understood as a claim about every commitment THL was involved in, but rather an average. Some commitments were secured solely by THL, and THL is responsible for less than 50% of others. 
• We fully acknowledge the imprecise nature of this multiplier. We explored taking a more granular approach, but ultimately decided against it. THL has limited data estimating our role in particular policies, going back three of the ten years included here. The data we do have gave us confidence that the 50% multiplier was conservative, though we acknowledge the bias that may be present here. We were highly skeptical of the value of generating post-hoc estimates to fill in missing data, both in terms of accuracy and as a use of THL staff time. We have noted this as an area that we hope to improve for future estimates.

Cost of Acquisition & Accountability: The total cost (actuals) spent on THL’s Corporate Cage-Free program work from 2015-2024. 

• This includes both the initial cost to secure a new corporate cage-free commitment through private negotiations and public pressure campaigns, as well as the long tail costs incurred to research, monitor, re-negotiate, and re-campaign for fulfillment of those commitments. 
• We used THL’s actual financial data to sum these costs. This includes allocating THL’s overhead expenses pro-rata. THL does not track costs on a per-policy basis. We used retroactive time allocation to partition spend between THL’s programs, relying on historical time estimates shared with ACE and other evaluators to assist with accuracy. 
• We have explicitly excluded expenses outside the scope of THL’s corporate cage-free campaigns, including but not limited to broiler welfare work, movement building work (including via the Open Wing Alliance and Animal Policy Alliance), ballot initiatives, research, veg advocacy, and grants to other organizations like THL UK.
• We adjusted all historical costs to constant 2024 US Dollars to account for inflation, using the Consumer Price Index (CPI) from the US Bureau of Labor Statistics. 

Additional Assumptions & Limitations

Counterfactual impact: Based on the experience of our campaigners and examples seen in Europe and Australia, we believe that if THL (and other animal activists) do nothing, hens have a near-zero chance of being spared from cages. We don’t find evidence that hens will eventually be spared from cages without advocacy compelling.

Binary outcome: This model calculates a binary outcome (hens moved from caged to cage-free). It intentionally omits calculations for animal life-years or discounting for time. We prioritized accessibility over granularity in the model, and acknowledge that this means that as a result we cannot quantitatively compare a commitment fulfilled next year versus one fulfilled in 5 or 10 years.

Reporting lag: The final calculation is a point-in-time estimate of a dynamic, multi-year process. The number will and should evolve as companies report new data, as fulfillment rates change, and as we accrue additional corporate cage-free policy acquisition and accountability costs. There is a time delay between securing a corporate cage-free commitment, funds spent to hold the company accountable for its commitment, and the ultimate fulfillment of that commitment resulting in hens spared from cages. This is compounded by the fact that we don’t get full reporting from all companies—some companies only report upon fulfillment, and our calculation would reflect the interim years as 0% despite likely incremental increases. This means that some costs are frontloaded into the calculation, and it would not be accurate to generate annual cost-effectiveness estimates based on the funds spent and hens spared in a single year. Rather, this estimate represents a holistic assessment over time, which we feel more accurately reflects the long-term nature of our work. Policy fulfillment data and hen estimates for this analysis were captured from our records in August 2025. This ensures the inclusion of a portion of prior-year progress reports, which companies typically provide by the end of H1 (June), helping to mitigate some of the inherent reporting delays. 

Future uncertainty: In some parts of the world, accountability work is getting harder, as the most willing companies have made progress and the most stubborn remain. This means that costs have the potential to increase at a higher rate than hens impacted in the near future, though it is possible this will be offset by work in other parts of the world. The increasing difficulty might reduce our cost-effectiveness over time. At the same time, there may be a tipping point that reduces the funds needed for accountability work. We hope that this evaluation demonstrates that regardless of fluctuations in the real-world difficulty of systemic change, cage-free campaigns remain a highly cost-effective and worthwhile intervention.

General uncertainty: We’ve rounded our estimate of the number of hens to a whole number. A cost effectiveness estimate is just that—an estimate—and we want to avoid giving the illusion of certainty by providing a more precise number.

Future Work

This represents our initial attempt at estimating the cost-effectiveness of THL’s corporate cage-free campaigns. Moving forward, we will continue collecting relevant data to iterate on our methodology and improve the accuracy of this estimate over time. We will determine a frequency to update this estimate based on internal capacity, likely every or every other year. In addition, we hope to conduct cost-effectiveness analyses of THL’s other programs.