minecraft-assets/assets/minecraft/models/item/lead.json

{
    "parent": "item/generated",
    "textures": {
        "layer0": "item/lead"
    },
    "display": {
        "head": {
            "rotation": [ 0, 0, 0 ],
            "translation": [ 2.75, -2.75, -6.5],
            "scale":[ 0.8, 0.8, 0.8]
        }
    }
}