Since someone who cares about pigs in the first place wouldn't be breeding them, breeding, showing, etc. are all only done by people who consider their own personal stuff more important than the welfare of their pigs. Simple numbers and genetics make it imposible for a breeder to "find a home" for every pig they deem "terminal" (non-breedable). The breeder standard of "90% terminal, 10% breedable" that is often quoted in the rancher world is reached today with technological wonders like artificial insemination and sophisticated genetic tracking and computer modeling, most breeders don't have access to these so the reality with most breeds is a 5% or less ratio.
This means that even the best breeder has to get rid of 19 out of 20 pigs born, and that every generation he must grow his number by 20 times in order to keep the same number of breedable pigs (typically around 25). Certain breeds have a high percentage of "lethal" births, 25%, try to find a home for the lethals that don't die... Imagine trying to find homes for hundreds of pigs every couple of months, that's several pigs a day. The reality is that breeders are killing their pigs in one way or another -- gas chambers or selling them to reptile owners as "feeders" or just taking them outside and 'letting them go', etc.
There was a thread that a breeder who passed and left his pigs behind in the world, about 500 pigs in all, he was pretty typical, some breeders will have a little more, some who are just 'getting started' will have a little less. The simple fact is that with that many pigs, you just can't afford the necessities of a good life for the pigs; in a breeders "care" the pigs' lives end up being awful.
