minecraft-assets/assets/minecraft/blockstates/sniffer_egg.json

{
  "variants": {
    "hatch=0": {
      "model": "minecraft:block/sniffer_egg_not_cracked"
    },
    "hatch=1": {
      "model": "minecraft:block/sniffer_egg_slightly_cracked"
    },
    "hatch=2": {
      "model": "minecraft:block/sniffer_egg_very_cracked"
    }
  }
}