animals does not spawn

Version of 1.12.2, version of 1.7.3, Single Player

Screenshots encouraged

The (vanilla) spawning manager spawns most passive mobs (like animals) when a chunk is created for the first time. Then it significantly slows down and occasionally spawns new animals in already generated chunks, but only if the passive mobcap isn't full. If you can't find any Animania animals, try to remove (kill) all existing animals or to generate new chunks in your world.