The parts of the pig that you cannot eat are the hair/bristles and the contents of the pigs digestive tract certain organ tissues like lungs if they are contaminated.
Although most other parts including the pigs liver, skin, blood and feet as well as the pigs kidneys, heart and spleen are edible and can be eaten.
The hair and bristles of a pig are used for brushes and the bones of pigs are sometimes used for broth and the pigs head and feet are used in stews, soups or as delicacies and the skin is often eaten as snacks like pork rinds or used in dishes.
The blood of pigs is used for blood sausage and the pigs intestines are processed into sausage casings.
Bacon is often made out of piglets as most piglets are slaughtered for bacon at around 22 weeks of age.
Pigs that are reared for smaller pork joints are often killed at around 15 weeks to 16 weeks of age.
And pigs that are reared for bacon are usually slaughtered or killed at around 22 weeks of age.
Bacon is sometimes also adult pigs as well.
Pigs are slaughtered at different ages, although generally they can be divided into piglets, which are 1.5 months to 3 months of age.
And the fattening of pigs that are intended for pork and bacon, which are 4 months to one year old.
And older pigs, like sows "female pigs" and boars, which are uncastrated male pigs.
Bacon is reserved for the cured pork belly cut of a pig.
The bacon is a cured meat from various fatty parts of pigs, which is primarily from the pork belly also known as streaky bacon, although the loin, "back bacon/Canadian bacon" or even shoulder, with the specific cut of meat from the pig, defining the type of bacon, which is all derived from swine.
Pork belly is the most common sauce of bacon, which gives American style streaky bacon with alternating fat and meat.
Pork loin is the back of the pig and is used for Canadian bacon, which is a leaner and rounder cut of meat.
Pork Jowl/Cheek is for jowl bacon.
And pork shoulder/butt is used for cottage bacon or collar bacon.
Bacon is made by curing the pork cut, which is usually belly with salt, sugar, nitrites and other flavorings, like maple, smoke etc through dry curing or brining.
And after curing the meat, it's often smoked, chilled, pressed, sliced thin and packaged.