Before we start, it's important to note that Chihuahuas can develop food allergies at any stage in their life. Even if they've eaten the same type of name brand dog food for years, their body chemistry could change all of a sudden, causing them to experience an allergic reaction from it.
The crew also filmed many scenes in the north of Vietnam, as well as Oahu, Hawaii. No doubt the shots of Vietnam's tangled jungles helped to establish Skull Island's authentic 1970s feel. Check out the island for yourself in the trailer for Kong: Skull Island:
But RKO referred to it as Skull Island in their publicity materials. Kong: King of Skull Island, a 2004 sequel-novel which ignores Son of Kong, makes an attempt to reveal the history of Skull Island before the events of the 1933 film's story.