Average life-span of a domestic pig is just over six months. That's because that's when 95% of them go to butcher.
In the wild the average life-span is probably considerably shorter - predators eat most of them in the first few months of life.
There are reports of pigs living as long as 16 years or more but that's like saying people live to 120 years of age. Yes, a few get that old, and older, but it is extremely rare. The reality is the average life-span, aside from market hog finishers, is more like six to eight years for pigs and 70 years or so for humans.
Our older breeder pigs have been seven to eight year end of age. Once they are no longer breeders for sure I slaughter them - that is a lot of meat that I don't want to waste. Putting the old animal out to pasture is a quaint idea but a farm has bills to pay and the banker, taxman, etc aren't interested in providing a rest home for old livestock. I don't run a sanctuary. I run a business. This is my income, how I pay my mortgage, taxes and put food on the table for my kids.
A big old sow or boar can mean $1,500 to $2,000 in income easily as hot dogs or sausage. Personally, I love the meat - it is delicious. More flavorful than young finisher hogs.
If we let them they would live a couple more years perhaps. The key is to catch them after they're no longer good breeders but while they're still good meat. We generally slaughter a dozen or so older sows a year. Theoretically you might spread them over the year but I tend to bunch them up in the fall somewhat because winter is the harshest season. Both livestock, wildlife and people are more likely to die over the winter. Better to slaughter them now in the fall when they are at their finest if you don't think they'll make it through the winter.
I figure, based on observing how pigs age, that one calendar year is about equal to ten human years. This analogy doesn't quite work out since pigs come into breeding age at about eight months which would be roughly like a seven year old human. Humans are developmentally delayed. But if you ignore that and observe the wear and tear of life an eight year old pig looks similar to an eighty year old human in good health.
Sugar Mountain Farm
Pastured Pigs, Sheep & Kids
in the mountains of Vermont
Read about our on-farm butcher shop project: