What is the reason pigs are always fat?

They're not always fat. Domesticated pigs in captivity are usually fat because people feed them too much. They've also been bred to eat and eat, so they put on weight and grow as fast as possible to make a nice, heavy carcass for the market. read more

If you mean farm-raised pigs for food, that’s because they are fed a lot in order to make them fat, because fat tastes good in meat. But pigs don’t have to be fat. They have naturally round bellies so even at healthy weights they tend to look rotund, and certainly they love to eat like most mammals. read more

Pigs are not necessarily fat (although some are), they look large because of the length of their body core and their short legs make them seem like they are fat. Pigs carry alot of meat on their carcass due to the rates that they grow. read more

So the reason why a farmer chops off a pigs tail is if they don't they other pig will eat but it doesn't stop there. Once the pig has got a taste for blood it literally starts to eat the other pig from the inside out devouring what used to be it's pen pal. Hope that answers your question. read more