Vintage Story delivers a number of game mechanics that allow the domestication of some of the animals that roam the world. After 50 generations chickens and baby animals will no longer flee from the player. Boars and Bighorn sheep still will become aggressive when attacked however.
Boars and Bighorn Sheep
When provoked with a weak attack, boars and sheep will try to attack you. You can use that behavior to guide them into your carefully prepared animal pen. In order for them to multiply you need at least one male and female as well as food placed in a large trough. You can feed them either portions of 8 dry grass or 2 grains. After eating a number of portions they can become pregnant and after another couple days later bear offspring.
Wild Chicken always try to flee form the player, again, you can use this to your advantage, just in the opposite way as its with boars and bighorn sheep. Chicken will only eat grain placed in small troughs and also require a male and female to be present. One added bonus with chicken is that hens will lay eggs on the ground every 8-15 in-game days. You should pick them up regularly however, as they disappear when not collected for 2 days.
Foxes, Wolves, Locusts and Drifters are considered wild creatures and cannot be domesticated at this point.