In Minecraft, there are many neutral wild animals. Each has its own use or produces something you can use. They the majority spawn on grass/dirt blocks in light. Except for squid, it spawns in water.
Produces-Feathers and Eggs
Overview-Chicken are a unique animal. When alive, they wander around and at some point may create an egg (which is needed to make cake). Once you kill a chicken it may drop feathers. The problem when killing chickens is with its size. It is quite small and once you hit it it will jump, making more difficult to hit.
Overview-Pigs are average sized, pink and have one use. Obtaining pork chops. If you kill a pig plain off there is a chance that ot will drop a raw pork chop. If you kill it while it is on fire there is a chance it will produce a cooked pork chop. A raw pork chop heals one and a half hearts. A cooked pork chop heals four hearts, making it completely superior to the raw pork chop.
Overview-Sheep are very beautful animals, untill you punch them and all their wool goes flying off!This is the only way to obtain wool as you don't get it from killing the sheep. This is really one of the only animals you can farm because it frows back its wool.
Overview-Wolfs are found anywhere. Although they do not produce anything they can be turned into companions if you use a bone on them. They will then follow you around and attack what you attack.
Overview-Cows are large. They are easy targets because of their movement speed and size. They are usefull because they will give you leather, the least effective armor.
Overview-Squid spawn in water. This makes them somewhat difficult to kill but it isnt that much of a problem. Once you kill a squid it may drop an ink sac, capable of dying something the color black. This is really not of any use.