I can't speak to rats specifically, but in my state feral hogs are a problem. The state wildlife office doesn't let hunters take them on public land, because it makes them skittish and they stay spread out (you can take them on private land with a landowner's okay, though).
They set up baited traps where a giant cage is suspended, which then falls onto the whole...team. (I looked up the word for a group of hogs)
Anyway the relevant bit is that supposedly, each year you have to kill/remove 60% of the existing hogs just to maintain the current population
> They set up baited traps where a giant cage is suspended, which then falls onto the whole...team
Have you seen this? Normally the gate drops only. Many ways but what seems normal in my experience, guys set up a trap with multiple entry/exists with food inside. Over time they reduce to one entry with a gate that has a trip wire or more commonly these days a camera with remote control gate release. Sometimes people use wire mesh panels overlapping to create a gate that pigs can push through one way only too.
We just had a massive boom where I am. Pigs foraging within 10m of the house (normally they would never be within 100m) and moving further into our valley than we'd ever seen before.
A sibling comment to yours included a link to a youtube video demonstrating exactly what I was talking about. They talk pretty extensively about different types of traps and their effectiveness during what seems like fairly extensive research.
My superficial googling suggests pig and hog were once, like piglet, developmental subcategories of swine (unweaned and ready-for-market). Like shoat (weaned), and gilt/sow (female that hasn't/has reproduced). But meaning has blurred and diversified since.
They set up baited traps where a giant cage is suspended, which then falls onto the whole...team. (I looked up the word for a group of hogs)
Anyway the relevant bit is that supposedly, each year you have to kill/remove 60% of the existing hogs just to maintain the current population
Needless to say, doesn't seem like it's working.