Scientific understanding of farm animal sentience has advanced dramatically in recent decades. This evidence base supports expanding moral consideration to include billions of farmed animals.
The scientific case for farm animal sentience is now overwhelming, transforming the ethical foundation of animal agriculture. Pigs show emotional contagion, preference for positive states, and signs of playfulness. Cattle form friendships and show excitement when solving problems. Chickens demonstrate numerical competence and self-control. Sheep recognize and remember individual faces. This cognitive and emotional complexity means that the suffering caused by standard farming practices is not trivial discomfort but genuine psychological and physical harm to beings capable of rich experience. The moral circle has been expanding throughout human history as we have recognized the capacity for suffering in previously excluded groups. Farm animal sentience evidence is the scientific basis for including them fully.