The Saipan Junglefowl was likely introduced to the island of Saipan by Austronesians seafarers.
It is thought to have been brought into The United States of America by returning American servicemen at the end of World War II including B. W. Saylor, who wrote "The Saipan Jungle Fowl" in 1977. Although the birds encountered at that time were both domesticated and wild on Saipan, it is thought that the wild ones were feral and descended from those brought in by the original human inhabitants. An alternative theory is that they were brought in by the Japanese as occurred in other locations such as Taiwan during the Japanese colonial occupation.
There were also feral junglefowl introduced to the Solomon Islands which are descended of normally proportioned, wild birds imported from Indonesia and beyond. The combination of the Comoros Island Giant Junglefowl and the domestic descendants of the Red Junglefowl produced the Saipan, Shamo, Malay, Koeyoshi and Asil.