My sow had just two babies that survived and they grew at an amazing rate. It got me thinking about the wisdom of breeding pigs for large litter size. The sow can only eat so much and put so many nutrients into her milk. We've seen from dairy cows that the more milk they give, the poorer quality it is, because there's a limit to their digestive system on how many nutrients they can process and pass through in a given amount of time. With pigs, I've read the sows must put on fat before they deliver because they cannot eat/digest enough fat to keep the fat up in their milk and they will lose most of their body fat while nursing their babies (tho some very well-fed pigs don't but I want mine to live on pasture).
Runts often don't thrive because they're weaker and get the farthest nipples that don't give as much or as rich milk as the ones the strongest piglets go for. Pig-raising conventional wisdom says those stronger, better fed piglets grow faster for their entire lives, to be the best meat pigs. When my daughter's pet hamster surprised us with a litter of 17 babies, they needed supplemental feeding from a very young age because the mother couldn't make enough milk for all of them, and they wound up undersize and most didn't live the full lifespan, so there may have been long-lasting health effects as well. It seems to me, with a smaller litter size, there is less competition and better quality and amounts of milk for all the babies. So if we're breeding pigs for our own use, and want the best, healthiest offspring, would it pay to breed for SMALLER litter size and get faster-growing, healthier offspring?