Three rare maleo chicks hatched successfully after months of carefully controlled incubation at the Bronx Zoo in New York City.

The maleo is a peculiar bird about the size and shape of a chicken with distinct peach plumage, an ocher beak and a knobby black helmet-like growth on its head called a "casque."

The three new chicks join six other fully-grown maleos at the Bronx Zoo, which claims it is the only place in the world to see maleos outside their native Indonesia.

"We've bread thousands of different birds but the maleos are the species we're the most proud of," said Mary Iorizza, collections manager at Bronx Zoo, in a YouTube video regarding the rare birds.

The birds are found in the wild on the Indonesian island of Sulawesi, but seeing them there is increasingly rare because of human interference and hunting.

"Maleos are extremely rare," said Iorizza. "Their land is encroached upon and their eggs are hunted for food."

Maleos are members of the megapode family, which do not use body heat to incubate their eggs. Instead, maleos bury eggs in mounds of decaying matter or other geothermic areas like warm sand.

"Almost half of all megapode species are threatened with extinction," said Nancy Clum, curator of ornithology at the Bronx Zoo, in a statement." The work we do with maleos both at the zoo and in the field can provide a model for conservation of other megapode species."

Because the maleo eggs have a lengthy incubation period, the chicks hatch mature enough to dig their way out of as much as three feet of sand.

The maleo chicks are left by mother birds to incubate on their own and can fly, forage and thermoregulate the day they emerge from the eggs.

The maleo eggs were unearthed after they were laid by the mother birds and placed in a carefully controlled environment for study and hatching. 

The chicks were born healthy are are currently in an off-exhibit area of the zoo.