A tool enabling animal welfare to be benchmarked across countries would make it possible to monitor and compare the status of animal welfare at both disaggregated and aggregated levels. The results of the international benchmarking would be useful for a wide range of stakeholders taking a positive interest in farm animal welfare. We aim to build a model for pigs and chickens with the following elements: (1) for each type of animal production considered a number of parameters linked to housing and management are defined. The parameters relate to features of production that are modified in legislative and market­driven initiatives to improve welfare; (2) by means of assessments made either by consumers or by experts, each value of these parameters is assigned a weight; (3) in each country the welfare level (beyond the basic level defined by EU regulation) found in the production, or the consumption, of pork and chicken meat is calculated; (4) the total state of farm animal welfare across different forms of production (here only two forms) is calculated for each country. A number of ethical considerations must be addressed in the process of building the model. In the paper we explain how we deal with several considerations. First, we focus on how to measure what affects animal welfare – whether the focus should be on environmental or outcome-based measures. Second, weights will need to be assigned to the different parameters, raising the question whether this should be done by animal welfare experts or consumers. Third, it will be necessary to decide what to include for each country and specifically whether it should be the welfare of animals produced in a country, including exports, or the amount of animal products consumed in the country, including imports. Fourth, a decision will need to be made on how to add welfare across pigs and chickens and whether to count number of individuals, the volume of products or the value of products.