Yes, the giant chicken in that YouTube video is real. This is the breed you see in that video. While this breed does grow to be enormous, the chickens in the video are exceptionally large.
The standard breed of Brahma Chickens is a heavy bird named for the Brahmaputra River in India, the Brahma is thought to have developed by certain crossings of other Asiatic like the Chinese Shanghai, commonly known as Cochin Chicken, and the Chittagong Chicken. Light Brahma Chickens are a fancy breed with fully feathered shanks and feet as well as a red pea comb. This pretty chicken breed is a good winter layer of brown eggs and an excellent source of chicken meat.
A massive breed, the Brahma roosters can get up to 12 pounds and the standard hen’s weight is around 9.5 pounds. Though the breed is slow to mature, it is a good layer of medium brown eggs and is extremely hardy in hot and cold conditions. The hens’ egg production may decrease if they are allowed to get too heavy.
The Brahma Chicken tends to be a gentle breed of chicken and they are good and frequent brooders. Brahma Chickens are an excellent dual-purpose chicken breed with ample utility on the farm as well as having a gentle character and unique feather features. The Brahma is sold in Buff, Dark, and Light color varieties.
Light Brahma Chickens are patterned similarly to the Buff but are mostly white with white laced black feathers around the neck, tail, and feet. The Light Brahma will also have solid black feathering at the end of their tail.