Animal welfare is a core focus area within effective altruism. It focuses on ways to improve the wellbeing of nonhuman animals, primarily in factory farms and in the wild.

Animals currently make up the vast majority of sentient beings. As many as 2.8 trillion animals might be killed for food each year, and there are many more wild animals.^[1]  Although many experts agree that animals display some signs of sentience, it remains an open question which animals are sentient, and how we should compare welfare between different sentient species.

Despite its importance, animal welfare is highly neglected: animal charities receive only 3% of charitable donations, and 99% of that money is focused on pets, who make up less than 0.1% of all domesticated animals.^[1]

The area also appears to be somewhat tractable. Open Philanthropy estimates that past corporate cage-free campaigns have spared about 120 years of suffering in battery cages per dollar donated.^[2]

Some people focus more narrowly on farmed animal welfare or on wild animal welfare.

Some have argued that, if one takes the view that future beings matter morally, interventions that seek to improve short-term animal welfare may not be as cost-effective as interventions that seek to influence the far future, given the astronomical number of animals that could potentially exist. In response, others have argued that attempts to improve short-term animal welfare will also have strongly positive indirect long-term effects.^[1] An objection to that argument is that it would be remarkable if an intervention selected for its short-term effects just happened to have better long-run consequences than all other interventions.^[3] In addition, critics have noted that there are theoretical reasons for expecting interventions focused on humans to have better long-run effects than interventions focused on animals.^[4] The considerations bearing on this issue are numerous, complex, and hard to assess, and the debate is currently unresolved.^[5]