I went to a sale at the Winger sales barn one year and a man brought in about 15 big sows. Each sow SHOULD have weighed about 500 lbs. I bought 2 of them for 10.00 each, and they scaled at about 275 each. When have you ever seen a pig where you could see all the bones in their face, even the fat in their tails was gone. After a deworming and 2 months of free choice feed, they were fat and sassy. Both sows went on to be excellent mothers. All the man had to do was feed them.
And what did they say at the sale barn? Nothing. Said they were "just wore out". Bullcrap. They needed feed!