Motivation is a central concept for animal welfare; it has inspired methodological breakthroughs and generated a wealth of crucial empirical work. As the field develops beyond its original mandate to alleviate the suffering of animals in intensive farming systems, the assumptions behind the current models of motivation may warrant closer scrutiny. In this paper, I examine some of the complexities of studying motivation — for example, that what an animal wants can depend on its welfare and that, through genetic selection and housing choices, we can modify what an animal finds to be rewarding versus punishing. The central theme of this paper is, therefore, that we cannot just ask the animals under our care (or even in the wild) what they want and assume that we will receive unadulterated answers, free from human influence. While asking questions about animal motivation with empirical research is invaluable and necessary, our models drive our research questions, methodologies, and results’ interpretation. When the models we employ remain implicit (eg the only motivation questions worth asking are those that could be implemented within the current housing systems), they have ability to stifle progress in understanding animal welfare. Thus, in addition to the empirical work, we also need to expose and evaluate the models that drive the research. Making the models explicit will facilitate our ability to identify their areas of silence, assess their strengths and potential limitations, as well as examine how they conceptualise the relationship between motivation and animal welfare. I end with a discussion of the implications of a few relevant models, both implicit and explicit, noting how such consideration reveals exciting areas for future work, including, for example, research on the motivation to make choices and the motivation to learn.