The sniffer egg was recently added in the latest preview/beta, however, you cannot obtain them naturally in survival via archeology inside the suspicious sand in the warm ocean ruins, since the loot table hasn't been updated yet to match Java, most likely because the rest of the Trails and Tales feature are still locked behind experiments toggle.
Step to Reproduce
- Enable the Next Major Update toggle when creating new world.
- Find a warm ocean ruins.
- Brush off the suspicious sand in hope that you get it
You have a chance to find the sniffer egg.
You can't find the sniffer egg at all in survival.
The warm ocean ruins archeology loot table on Java here:
The warm ocean ruins archeology loot table on Bedrock here: