The only thing spawning is enemies in the overworld. In 4 full 1:16 maps I have been unable to find more than 5 animals total per map. Every other version I play, there would be packs of cows and pigs all over the place. Additionally, there are no monster spawns in the nether except for pigmen. No ghasts, no slimes, no wither skellies, no blazes either except for ones coming from spawners and they 1-shot me in full armor and fire resist potions(which I expect is an entirely different issue).