So for the rankup to JrFarmer++ you need 10 bats.. unsure of other needs or uses but after that rank it could be a cool implement to pick a recipe for bat spawners, maybe needed and uses for rankups in the future? That or even just the addition of a bat spawn egg.
Hiya, Spooks~! This probably won't happen because it's a rank up requirement, we have common animals spawners but the bat requirement is supposed to be hard.