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:
Denham survives unscathed. Skull Island is never referred to by name on film. In the original film, only Skull Mountain is named, while in the sequel Son of Kong, its simply referred to as Kong's Island. In the novelization of King Kong (1933) by Delos Lovelace, it's called Skull Mountain Island. But RKO referred to it as Skull Island in their publicity materials.