Examples of the formation of free groups of cattle (Bos taurus) are considered on the example of the Slobozhansky herd and two other groups remote from the Luhansk region—the Tendra and Chernobyl groups. The Luhansk herd was formed as a farming experiment; it existed from the early 1990s until around 2007, reaching ca. 40–50 animals in peak years, surviving cold winters and summer droughts well, but eventually being depopulated by poachers. Other groups were formed under different circumstances. The Tendra group is a herd of up to 100 animals that lived in the natural boundaries of an essentially island-like location; it was annually renewed with young animals, up to 30% of the herd, and animals were also taken from there for the needs of the military. The Chornobyl herd was formed from escaped cows and is constantly monitored. Finally, significant progress has been made in the Beremytsky Park as part of the international project Aurochs 2.0. The history of herd formation shows that animals are highly adaptable to exist without human care, provided that there is little or no human removal. These examples demonstrate the effectiveness of using different cow breeds for rewilding programmes.