Minecraft wiki entry for Ranching, associated text: Animals in an open setting may be difficult to breed. Because of this, most players find it easier to construct fences for animals to stay. Even a medium-size pasture can result in animals neglecting to notice one another in love mode. Animals will spawn in the same square as their parent. It should be noted, however, that if they are in the same square as a fence, glass pane, or other item that takes up only part of a square, offspring may spawn in or on the other side of the block.