During the harvesting of a pig, a farmer said to me that the pigs understand fear but do not understand death. Seemed pretty reasonable to me in how pigs reacted to their dead friends; they weren't much fazed.
Of course, the hypothesis that they are sufficiently aware of everything -- existing and being nurtured solely to be slaughtered, having already seen many friends die, if female having had many children stolen from them -- to be traumatized to the point of utter emotional breakdown and unfeeling is also consistent with said observation. Humans who have survived war crimes and horrific battles tend to go pretty dead-eyed too. Death might even be welcomed, as a deliverance.
I know these pigs hadn’t seen death or had that kind of loss. Your idea here is important, but overplayed. It’s important because we have not given animals enough credit, but it’s overplayed because you’re giving them way too much human characteristics. For starters, they don’t have language, so their depth of thought and feeling are not similar. Imagine what they think about the origins of food. Hint: basically zero idea. Their thoughts on death and loss will be similarly weak.
That you seem to consider yourself sufficiently expert and authoritative to declare the idea "overplayed" -- and that you consider this declaration something that will further readers' understanding (which I at least view as the goal here) -- is... let's say, interesting.
In any case, no, I certainly would not attribute to pigs human-level cognition. But certainly, the notion that language is a prerequisite for thought (at least up through the level of "solving a Sudoku puzzle", per some research) has been largely discarded [0]. And certainly, as omnivores (who will kill and/or consume members of their own species, occasionally including even their own offspring, as well as members of other species) I think it's reasonable to suppose that pigs would have an inkling that one being's death is another's meal. And fundamentally, there is ample reason to suppose that pigs are closer to human-like cognition than the vast majority of species on earth. (Anecdata: they make for difficult pets owing to their need for stimulation, they can play video games [1], and -- as any reputable animal scientist will tell you -- once you get past certain bare-minimum things like ending the use of gestation crates, the most important things for pig welfare in industry are not group housing or (beyond a certain point) extra space, but rather giving them toys and a sense of cleanliness via clean bedding.)
But feel free to provide evidence that attests that "[t]heir thoughts on death and loss will be similarly weak." I would certainly take it into consideration.
It is possible that some of our now extinct sibling species also weren’t fazed that much by a dead fellow. It depends on default settings of a character and may be orthogonal to subj. The same stands for humans, some cultures celebrate the death.
This is not my experience at all. And I’ve been quite shocked by what farmers I know have told me about how pigs treat injured brothers (eating them alive). And yea, they weren’t starving.
I am basically an animal intelligence/emotional range maximalist but that doesn’t mean they respond the same way we do.
Well, I can't speak to what conditions your pig farmer friends keep their pigs in, but none of the dozens of pigs I've ever raised had ever shown any kind of inclination towards cannibalism. Sows eating their own piglets is the closest I've heard in natural conditions, but there is probably some deeper evolutionary reason behind that and not just like "oh nice, an easy meal!"
