Nexan-s_Custom_Resources/assets/minecraft/models/item/chicken.json

{
  "parent": "minecraft:item/generated",
  "textures": {
    "layer0": "minecraft:item/chicken"
  },
  "overrides": [
    { "predicate": {"custom_model_data": 1}, "model": "custom:item/buttercupcookie"}
  ]
}