Cracklings

Cracklings, also known as scratchings, are the solid material which remains after rendering animal fat and skin to produce lard, tallow, or schmaltz. It is often eaten as a snack food or made into animal feed. It is also used in cooking.
Cracklings are most commonly made from pork, goose, and chicken, but are also made from other poultry and from beef, mutton, and lamb.
Sources.
All.
In French cuisine, cracklings ("grillons", "grattons", "gratterons", "frittons") may be made from pork, goose, or turkey. These are salted while hot and eaten as an hors-d'œuvre, especially in the southwest.
Pork.
Pig skin made into crackings are a popular ingredient worldwide: in Central European, Quebecois ("cretons"), Latin American and Spanish ("chicharrones"), East Asian, Southeast Asian, Southern United States, and Cajun cuisines. They are often eaten as snacks. In Hungary, they are popular as a breakfast or dinner food.
Beef.
"Krupuk kulit" is an Indonesian cracker ("krupuk") made of beef skin.
In Argentina and Uruguay cracklings extracted from tallow are called "chicharrones" and are a common filling for traditional breads.
Poultry.
Goose cracklings are popular in Central European cuisine.
Chicken and goose cracklings are popular in Ashkenazi Jewish cuisine, and are called "gribenes".
Lamb and mutton.
Cracklings from fat-tailed sheep were until recently a popular ingredient in Persian cuisine:
Uses.
Cracklings are used to enrich a wide variety of foods, from soups to desserts. Modern recipes sometimes substitute crumbled cooked bacon.
In German cuisine, cracklings of pork or goose ("Grieben") are often added to lard ("Schmalz") when it is used as a bread spread.
Crackling is often added to doughs and batters to make crackling bread (French "pompe aux grattons"), crackling biscuits (Hungarian "tepertős pogácsa"), or potato pancakes ("oladyi").
Salted cracklings are widely used as a snack food.
Cracklings have been used as a supplement to various kinds of animal feed, including for poultry, dogs, and pigs.