Hybrid pigs

Hybrid pigs are domesticated half-pig animals that form the basis of agriculture in many rural areas of both the Fire Nation and the Earth Kingdom. They generally resemble pigs, but have the physical features of other animals.

Known types
There are various types of hybrid pigs raised on Earth Kingdom farms, in Fire Nation villages, and by the Fire Nation military.

Moo-sow
The 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, used for food. Kept in pens by the Fire Nation military, they are also used for physical training.

Picken
The picken, or pig-chicken as the animal is referred to in the Fire Nation, is a cross between a pig and a chicken. This creature lays eggs which can be sold by the dozen, and its meat can be cooked in various manners to create a variety of dishes. The picken has the white feathers, wings, tail, and body of a chicken with the head of a pig; it also has a yellow beak. It is an especially popular type of livestock in the poorer backwater villages of both the Earth Kingdom and the Fire Nation.

Pigster
The pigster is the male counterpart to the picken, and a cross between a pig and a rooster. These animals are often used to wake up those living in rural areas.

Pig deer
The pig deer is a cross between a pig and a deer. The 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.

Wooly pig
The wooly pig is a hybrid of a sheep and a pig. This animal is bred for its wool, which can be used to create various types of clothing. Its wool gets particularly muddy, however, because the wooly-pig tends to roll around in muck. The wooly-pig can also be raised for its meat.

Connection
Each of the pig hybrids is a combination of a pig and an additional real world animal. The wooly pig is part sheep (although it also resembles a Mangalitsa, a breed of pig which has a fleece akin to that of a sheep), the moo-sow is part cow, the picken is part chicken, the pigster is part rooster, and the pig deer is part deer.

Trivia

 * The picken is one of the few examples for the regional differences within the language of the Avatar world, as it is referred as Picken in the Earth Kingdom, but called pick-chicken in the Fire Nation.