They're a "sporting" breed, bred specifically for their toughness...
Asils, Shamos and Malays
Well, Asils are the ancestors of the Cornish breed, so they look sort of like a more slender, athletic Cornish. The Asil developed in India as a fighting bird, but different than the English games--an Asil is like a boxer (versus a fencer) and is valued for stamina. They are heavy boned, heavy muscled, very hard feathered birds (bare breastbone), with somewhat of an upright carriage.
The Shamo is another of the hard feathered Game breeds; the breed was developed in Japan, but its ancestors came from Siam (now Thailand) between the 17th & 19th centuries (the Tokugawa period).
Shamos are tall, with a rather upright stance; they have the typical Oriental 'bird of prey" expression, with heavy brow ridges and short, sturdy beak. Eyes are usually pearl, the comb is pea, wattles are small or non-existent, and the feathering is exceedingly short and hard, to the extent that the breastbone is left bare. Although broad shouldered and heavily boned, they lack the exaggerated curves of the Malay, and are taller and less compact than the Asil. Tails are small, and generally follow the line of the back sloping downward to the ground.
This hard-feathered old breed arrived in England from Asia, possibly as early as 1830.
These birds are very long-legged, and the broad skull and projecting eyebrows give them a sinister expression. Malays have a strawberry comb. The outline of the back, from head to tip of tail, should describe 3 convex curves. One of the Game Fowl, originally used for cock-fighting, the Malay is quite pugnacious. It is intolerant of other roosters and may attack anyone who goes near it's hens.
My DS called THESE guys Raptor Legs when he was smaller: