There are some spawning rules in Worlds in Bukkit. They are:
Animal spawning can be split into the following categories:
To get the amount of animals that can be spawned inside the World at runtime, you can use the method
For land animals and
For water animals.
Both limits can be set with the methods
void setAnimalSpawnLimit(int limit); void setWaterAnimalSpawnLimit(int limit);
Note: If set to numbers below 0, world's default amount will be used instead.
Minecraft makes an attempt to spawn animals every 400 ticks (default). That can be changed if you desire, using the following signatures:
void setTicksPerAnimalSpawns(int ticks); void setTicksPerWaterAnimalSpawns(int ticks);
Note: If set to 0, animal spawning will be disabled for this world. It's recommended to use setSpawnFlags(boolean, boolean) to control this instead.