Hybrid pigs

Hybrid Pigs are half-pig domesticated creatures encountered by Zuko when he visited an Earth Kingdom farm. They generally resemble pigs, but have the horns and blotches of other animals. It is unknown whether they are bred for their milk or meat.

Known Types
There are various types of pigs raised at Earth Kingdom farms.

Wooly-Pig
A Wooly-Pig is a hybrid of a sheep and a pig. This animal is bred to make use of its wool, which can be used to create various clothing pieces. The wool gets particularly muddy, however, because the Wooly-Pig tends to roll around in the muck. The meat of the Wooly-Pig can also be used for food.

Moo-Sow
A Moo-Sow is cross between a cow and a pig. It produces a special and delicious pig-milk favored by the people of rural towns. The hybrid also provides rich meat that can be used for food. Apart from their appearance in "Zuko Alone", Moo-Sows were also featured in the comic "Private Fire". They are kept in pens by the Fire Nation Military, and are used for food and physical training.

Picken
A Picken is a cross between a pig and a chicken. This creature lays eggs that can be sold in dozens. It can also be cooked in various manners and made into a variety of dishes.

Pigster
A Pigster is a cross between a pig and a rooster. Not much is known about them apart from the fact that they make great alarm clocks. Along with the Moo-Sow, one Pigster appeared in the comic "Private Fire", though it was only seen for a brief moment. It can also be seen in "Zuko Alone", perched on a fence.

Pig-Deer
There is very little information known about the Pig Deer, apart from its physical structure. A Pig-Deer exhibits the facial structure of the pig and generally has the same body shape. However, each Pig-Deer has two antlers protruding from its head and fur covering its entire body. Pig-Deer are presumably hunted for their meat, most likely resembling venison and pork in terms of texture and taste.

Trivia

 * The Hybrid Pigs were Bryan Konietzko's least favorite animals, as he thought they took the concept of hybrid animals to a ridiculous extreme.