European bison (wisent) were extinct in the wild by 1927 and have been restored through captive breeding. American bison were nearly exterminated. Both stories involve significant welfare considerations.
Captive-bred European bison reintroduced to wild landscapes face the welfare challenges of animals bred in zoo conditions adapting to natural environments. Nutrition shortfalls in early winters after release can cause significant welfare harms. Social group dynamics among bison with limited wild experience can be abnormal. Bison-human conflict at habitat boundaries motivates lethal control that creates individual welfare harms. Yellowstone bison management includes hazing, capture, testing, and sometimes killing of bison that leave the park boundary — an intensive management regime with significant welfare costs. The long-term trajectory — restored wild bison populations living natural lives — represents genuine welfare improvement but the transition involves sustained welfare harms.