Breeding



Breeding is a game mechanic introduced in pre-release 2 of 1.9. It will allow fed animals to breed with each other to make new animals of that species. Notch most likely for fun tweeted: "You know what would be fun? If every single animal in minecraft came from eggs. Breeding would involve moving egg blocks around."

Current Mechanics
As of Beta 1.9 pre-release 3, Pigs, Sheep, Chickens, Cows, and Mooshrooms enter "love mode" if you feed them. Animals in "love mode" emit hearts at a constant rate and will path towards nearby animals of the same type that are also in love mode. After about a second, a baby animal of the same type spawns on one of the parents which both end love mode.

After the baby animal is spawned, the parents will follow it around, staying close to it, and occasionally circling it. Hitting the parent stops it from following the baby.

Currently, all animals are grain-fed and require two wheat to produce a single animal of any type. Despite laying eggs, chickens do not use them to breed. All sheep are born white irrespective of their parentage. Animals are uninterested in wheat lying on the ground.

After initial investment in a ranch, generally consisting of a small closed in area safe from hostile mobs, animals can essentially convert wheat into various resources at a constant average rate.

Ranching
Animals in an open setting may be difficult to breed. It may be easier to construct pens or find pastures for animals to stay. Even a medium size pasture can result in animals neglecting to notice one another in love mode. Animals will spawn in the same square as their parent. It should be noted, however, that if they are in the same square as a fence, glass pane, or other item that takes up only part of a square they may spawn on the other side.

Cows, mooshrooms, pigs, and chickens can all provide food when killed - this food will be cooked if they are killed with fire.

Cows and mooshrooms also provide leather, while chicken provide feathers.

Sheep will drop one wool when killed, however, shearing them produces 2-4 wool, and one dye can be used to color their wool before shearing (Making it 2 - 4 times more effective to dye and shear sheep than to kill them and dye the wool.)

Eggs can be harvested from living chickens, milk from living cows (with a bucket), and mushroom stew from mooshrooms (with a bowl.) Mooshrooms can also be sheared to produce red mushrooms, though they will then become normal cows.

Automated Animal Farms and Mass Breeding
Small scale automated breeding systems can be built by herding passive mobs into moving minecarts and summoning them to a central breeding location - this has the disadvantage of still breeding new mobs relatively slowly (one every five minutes.) Also, when saving and loading the game the mobs will "escape" from the minecarts - this can be dealt with by "storing" them inside of glass blocks. An example can be seen at DocMs Automated Breeding Machine

Mass animal breeding farms can be built by "Compressing" mobs into a very small number of squares using the CMC system. Mobs are "Squeezed" into a small area (Generally a three high 3x1 chamber) by pushing the walls around them closer with pistons, these animals can be bred to produce new animals that will remain trapped inside the enclosure and can be bred themselves - meaning that many many mobs will eventually be stored in the same square and can be fed simply by "Spamming" stacks of wheat into the enclosure. If starting with two mobs and feeding them for an hour while using this system (assuming no missed feedings or killed mobs) 56 adults and 28 baby mobs will be held inside the 3x1 cell. After two hours this would increase to 2349 adults and 1174 children (This is not recommended however, unless you have a VERY powerful computer!)

Chickens can be fed from through a half slab in the side of the enclosure or from above through a hole in the middle, other mobs can be fed through a 1 wide hole in the side of the enclosure without any risk that they will escape. Feeding the mobs once while harvesting, and once between harvests, is enough to keep mobs at roughly their current level - allowing the user to "dial in" the amount of mob drops gathered per harvest.

For a tutorial on building the farm, and automatic harvesting, watch Cake's Mob Compressor System

Baby Animals
In Minecraft 1.9 Pre-Release 3 Notch added baby animals, the offspring of cows, mooshrooms, sheep, pigs, and chickens. They are like a miniature form of the adult, but do not drop resources, and have the same head size as the adult. Though it is possible to shear a baby sheep for its wool, no other drops can be gained from baby animals. Baby animals grow into full sized adult animals in approximately 1 day (10 minutes). They can be found roaming the fields or can be bred by feeding animals into "love mode". The parents will follow the baby when it moves, but will not always follow the baby they spawned. If two pairs of animals are bred closely together there is a chance that both pairs of parents will follow only one baby.

Trivia

 * All sheep breed white sheep, no matter what original color the parents have. It is unknown if this is a bug or not.
 * Mooshrooms and cows can breed with one another, this may produce either a cow or a mooshroom. It is unknown whether this is a bug or not.
 * All of the cows in Minecraft are, by definition, female. However, because of the lack of bulls in Minecraft, they are able to produce offspring regardless. The same happens with chickens, as there lack roosters in the game. However, female chickens are called hens, and the Minecraft mob itself is called chicken, so it might be that they are male and female, only you cannot tell the difference between the two.
 * It is possible to breed Wolves with wheat. It is unknown whether this is a bug or not.
 * In 1.9 pre-release 3, animals breed baby animals, which have different sounds and are smaller. Lambs (Baby Sheep) drop wool upon shearing.
 * Baby animals do not drop any items on death because Notch does not want to encourage killing of baby animals.
 * Once 2 animals become parents they will follow the baby where ever it goes for five minutes.
 * Once the baby is born, the parents cannot enter love mode again for five minutes (half a minecraft day).
 * If you shear a baby mooshroom it will turn into an adult cow instead of a baby cow. This is most likely a bug.
 * You can ride baby pigs with a saddle.
 * You can feed neutral wolves wheat and they will enter love mode, but it is currently unknown whether they will breed.
 * Tamed wolves can only be fed wheat to enter love mode if they are afflicted by the bug that causes them to forever try to sit down, though again it is unkown whether they will (or can) breed.
 * Editing in a baby wolf crashes the game with a whitened Saving Chunks screen rather than the normal one.
 * When a baby pig with a saddle on it grows up, it keeps the saddle.

Bugs

 * If a single piece of wheat is used to make a mob enter love mode, the wheat will become an unlimited stack like in creative mode. (Fixed in 1.9pre3).
 * In SMP 1.9 pre4 there are no baby animal models. Instead animals that are bred just breed other adults.