Ecosystem-Based Automatic Passive Mob Reproduction

Summary: Allow passive mobs (that are naturally hunted by other mobs) to reproduce. They should need a large area to do it automatically, so players could even use this feature to make animal farms.

Core Mechanics: 

Two mobs of the same type will automatically breed if these conditions are meet:

• Mobs becoming "Content" after grazing naturally (e.g., sheep and cows eating grass (plants, not grass blocks) for 3-6 times). This could be shown by subtle visual/particle effects.
• Breeding mobs are in the same "herd", or "safe zone": An large area claimed by the mobs that have sky access and many grass plants around (somewhat like a villager can make a village by claiming a bed or workstation). This could be defined as 5 (or maybe more) grass plants (with sky access) per mob, including the one that would be created, within for example, a 3x3 chunk area surrounding the breeding mobs.
• Natural reproduction may fail if there's too many passive mobs in the area (e.g., more than 1 passive mob per chunk) and if they aren't in full health.

Key Benefits:

• Automatic Farms: Create spacious, secure pastures that generate animals without constant player intervention.
• Ecosystem Depth: Rewards players for creating safe, natural habitats. Links perfectly with plant regrowth mechanics (like Grass Sprouts).
• Optional & Non-Intrusive: The classic instant-breeding with food items remains unchanged. This is an added layer of depth for those who want it.