This page of the Valheim guide provides instructions on how to tame boars and how to breed them. Boars are dangerous animals that can as far as kill an unwary Viking at the beginning of their adventure in Valheim. However, they are also an excellent source of raw meat and leather scraps. As you progress in the game, the demand for both of these resources will only increase, so consider breeding boars so you won't have to scour the forests in search of free-roaming specimens. Below you will find a handful of information on how to start on it.
How to tame a boar?
In order to tame a boar, it must grow accustomed to your presence first. The best way to do this is to toss him food. Boars eat primarily raspberries, blueberries, mushrooms and carrots.
However, keep in mind that it is not until the 100% completion of the taming process that the boar will stop being hostile to you. Furthermore, the taming process stops when the boar gets scared (i.e. it is aware of the player's presence or is near a fire source, e.g. a torch). The process itself usually takes up to several days and requires several portions of food.
Therefore, the most effective technique is to lure the boar near some shelter and build a wooden pen around it. Once you catch the boar, drop some food into the pen (it may be food of your choice) and... wait.
Once the animal is tamed, you will get a pop-up notification and, if we are nearby, a sound signal. Tamed boars can be stroked (you will then receive information that they love you), but unfortunately they cannot be told to follow you.
How to breed boars?
Once you have captured and enclosed at least two adult boars, all you need to do is make sure that they always have something to eat in the pen. After some time, baby piglets will appear and will soon grow into adult boars. Importantly, boars are afraid of fire - if there is a campfire, torch or other fire source nearby, they will panic. Scared boars will not breed, so you should pay attention to this.
How to select a breeding boar?
Boars, like all other creatures in the game, have 3 levels of rarity, denoted respectively by zero, 1 or 2 stars.
The more stars a boar has, the more resources you will receive after killing it. Importantly, this trait is hereditary. For example, if you breed a zero-star boar with a 2-star boar, you have a chance of getting 2-star offspring. If you breed two 2-star boars, you have a 100% chance of getting 2-star offspring. Therefore, it is a good idea to capture at least one 2-star boar to make your breeding as efficient as possible.