This article begins somewhat oddly. No one is "turning pigs into cannibals". Pigs sometimes eat their young and will sometimes eat a dead pig, but they do not hunt each other or large game in general. I disagree with industrial meat on the whole, but feeding pigs pork is a lot more "normal" than giving cows feed containing cow blood and other beef byproducts, which of course is the cause of mad cow disease.
Which part, the eating of babies or the eating of a dead animal of the same species? Pigs are very opportunistic and will eat whatever unless they have a whole lot of choice. Or sometimes whatever is within reach. My pig (who was well-fed) ended up eating a couple ducklings and a young chicken that my then-girlfriend left in his enclosure with him.
Yes. Almost all of them come from the species Rattus norvegicus (white rats). However, within that species there are many strains of genetically similar animals that, say, are prone to diabetes or hypertension, or have differences in immune function. There's a million ways these animals have been bred for studying this or that disease.