Which breed is famous for being unable to fly?

The emu is well-known for its inability to fly, primarily due to its large size and heavy body structure, which is not conducive to flight. This flightlessness is a characteristic shared by many members of the ratite family, which includes ostriches and kiwis as well. Emus have small wings that are not sufficient to lift their bodies off the ground, and instead, they are adapted to running and can reach impressive speeds while on land.

In contrast, the other breeds listed are either capable of flight or, in the case of the Silkie, are known for having a different set of characteristics that do not include flightlessness as a defining trait. Swans are strong fliers, while Legbars have the capability to take off as well. Thus, the emu stands out as the breed specifically recognized for its inability to fly.