Often brightly colored with large, fan-like tails that can span 60 inches, peacocks are the male members of a species of bird know as peafowl, which are in the same family as the pheasants native to North America. Peacocks are often kept as pets or farmed for their beautiful tail feathers, which have made them a national symbol in India. Though majestic, these birds are almost entirely defenseless, allowing many different animals to prey on them.
TL;DR (Too Long; Didn't Read)
In natural settings, any large predator like leopards or dogs, may prey on peacocks.
The two main species of ornamental peafowl are the green and blue varieties. The green peafowl is native to Burma and Java, while the blue comes from India and Sri Lanka. These countries are home to a wide range of large hunters that are potential peacock predators, and peacocks have fallen prey to the likes of large jungle cats such as leopards and tigers, but also to smaller animals, like the mongoose or stray dogs.
The peacock is a proud animal that will aggressively defend its home as it does in the wild while searching for a mate. A peacock is often very territorial and may lash out violently against other fowl that invade its space, especially if the female -- a peahen -- is present in the picture. The green peacock especially has been noted to need special separation while in a zoo, aviary or other collective enclosure.
While certain species of peacocks are considered endangered, many people around the world keep peacocks as pets at their farms or homes. One often overlooked fact is that pets can pose an extreme menace to the peafowl. Dogs, even if well trained, can turn on a peafowl while somebody isn't around. For this reason, dogs must be kept separate from the peafowl at all times, lest the dog be too rough with the fragile bird. Even house cats can seriously threaten a baby peafowl.
Because the peacock is almost strictly ornamental, without any true means of self-defense, it becomes necessary, if raising a peacock in captivity, to defend it from predators. In the wild, the peafowl will roost in a tree overnight to keep away from predators, and this is the first place it will go if it feels threatened. As important as it is to keep predators out of the enclosure, it is equally important to give the peacock a method to escape should one appear by providing a tree or another high place to fly or climb to.