Update: A couple people had questions about Jacob's history in the story. He wasn't a wild or feral boar, but was instead an ungelded domestic pig. Thus he's used to people, but the raging hormones coursing thru his system makes him unreliable around people (which is why most pig farmers contract-out pig breeding to specialists).
In the beginning of "Grappling with Survival", Alice found Jacob on a domestic farm, trapped under his mother who'd collapsed on him when she died, before he'd been gelded.
Chapter 7 of "Seeding Hope Among the Ashes" has an entertaining history. At the conclusion of Book 2, "Grappling with Survival", David and the others found a wild pig. I originally wrote that "they couldn't tell whether it was a female or a wild boar". Not having spent much time on a farm, I missed a few details. Someone responding, explaining that you can't mistake a boar from a gelded pig, especially when seeing them from the back. Curious, I pressed for details (despite how disturbing the image he sent me was).
The results is "Chapter 7: A Pig in a Poke". That initial discussion planted a seed in my brain, which flourished over the next year. I think you'll enjoy the tale, even if a few details are still a little exaggerated for dramatic effect.
By the way, if anyone is wondering, "Fowler's Crossing" is David's home town. (After writing this segment, I had to go back and revise the first book, "Love and Family During the Great Death" to add that little detail to the story.