The pig is so good that we can use up every part of it, that is the idea behind an old Spanish saying that says "the pig is so good that I like it even when it walks". Obviously if we can use all of it, we have a great performance for nutritional purposes.
The chorizo is a good example of it. After the pig slaughter, all the different parts are separated according to their quality and final destination. In the case of the chorizo, some fat meats are chopped and mixed with spice (essentially paprika to give it the typical red colour) and stuffed into the same hog casings, once the mix is ready.
Then the curing time is quite short until the sausage flavour is homogeneous enough to be fit for the consumption. Depending on the final flavour that we want to achieve at the end of the curing time, we basically will follow two different curing methods: air curing or smoked.
In Spain, chorizo is produced where there is a tradition of pig rearing. The taste of chorizo will be according to the local curing method applied: some are intense and dry like the Cantimpalo Chorizo of Segovia, others like the Chorizo Cular of Avila are more intense and oily for stewing and/or frying.