TL;DR: This datapack allows you to get back the old animal spawning from beta 1.7.3. There will spawn a lot more animals in your world, so you dont have to breed animals anymore

This datapack allows you to get back the old animal spawning from beta 1.7.3. The animal spawning in modern minecraft is as follows:
From the Official Minecraft Wiki:

Friendly and water mobs have only one spawning cycle every 400 game ticks(20 seconds). Because of this, where conditions permit spawning, hostile mobs spawn frequently, but passive mobs (ie: animals) spawn rarely. Most animals spawn within chunks when they are generated.

The animal spawning in beta 1.7.3 is as follows:
From the Official Minecraft Wiki:

Mobs are broadly divided into three categories: hostile, friendly, and water (i.e. Squid).Each category has a spawning cycle once every game tick (1/20th of a second). Before these cycles happen, a list is built of every chunk that is within an 8 chunk distance of anyplayer, on both the X and Z axis. That's a 16x16 chunk, or 256x256 block area for each player. If this area overlaps between multiple players, the common chunks will only be added to the list once
....
If it's a passive mob other than Squid, then...
  -the block directly below the spawning block must be grass
  -the light level of the spawning block must be 9 or brighter

More information about this can be found in AntVenoms video:

https://www.youtube.com/watch?v=3d4THVvot8s

The datapack replicates this as follows: every game tick the game choses a random block in a 128x128 radius of a random player. If the block below is grass, and the light level above the block is above 9, a random animal of the following list will spawn. Animals that can spawn are a chicken, a sheep, a pig and a cow. The maximum number of animals that can spawn within a 128x128 radius of the player is 31. Animals despawn when they are more than 128 blocks away from the player.

That's pretty much it. Please leave datapack suggestions in the comment section!