You have such a human perspective on things. Pigs are free to find their own meaning to their lives as well. Why should they be concerned what their lives mean to us? Long and short are relative terms. For you 80 years is long, for me it's short. For you, 6 months is short. For a domestic pig 6 months is long because it's 100% of their lifespan. What's the median lifespan of wild pigs?

For us and pigs our lifespans are dictated by the realities of our environment. Humans are part of pigs environment.

As for miserability of existence, there's no treatment for Weltschmerz.