Growing up here, I'd never heard of a matanza, but after I moved back, I was hearing about them a lot. LOML and I went to one a year or two ago and it was a lot of fun. (Smaller than the one in the article you linked to, though. Just a single hog and few dozen people. It was still an all day and night event with people coming and going throughout.) It was a bit of culture shock for her, being a city girl and all, to see a table with 4 or 5 people cutting up a fresh-butchered hog into bite-sized pieces. (She's not big on eating pork anyway.) And then there were kids running around playing with discarded hog feet. But the hosts also had a couple of donkeys and a few brand-new baby goats for her to play with, so it was all good.
That is the place for good eats. Never happened when lived there. As a kid this occured in fall when not was butchered for winter food. Folks gathered and ate like crazy cooked over fire. The only way I like liver.
David