American bison have been partially restored to portions of their historical range, with welfare implications from managing large herbivores in fragmented grassland ecosystems.
Managed bison welfare depends significantly on herd size, range availability, and management intensity. Bison confined to small pastures cannot express natural ranging and grazing behaviors that are fundamental to their ecology. Culling operations to manage population size in fenced areas involve capture and slaughter that causes acute welfare impacts. Brucellosis management requiring vaccination and monitoring creates stress from handling and capture. The most welfare-positive bison populations are those in large protected areas where animals can move freely, engage in natural social behaviors, and respond to environmental conditions as they evolved to. Restoration of bison to large prairie landscapes allows welfare-appropriate lives while restoring ecological function.