Since I work with the animals with a minimum fence, most of what I do with them I have to do with their consent. It's much simpler to be able to deal with the animal in a friendly way and have your interactions be something that the animal looks forward to.
This boar was purchased at 4 months of age, and I've worked with him every day since then. The "boar tax" in this case is a back scratching, which is my excuse for having him stand still so I can look at him and make sure that everything is good. If you establish a routine that mimics what you'll need to do when you treat them for illness or wound you won't have a struggle when it comes time to do that.
So what I suggest you do with whatever animal you care for, is to establish a routine that looks like what a vet will do. In the case of pigs, its come when you're called, follow me (we cheat here and use a bucket of food) stand still while I touch you and walk around you out of your sight, and allow me to handle your head, ears and underside.
I have other folks to the farm, and from time to time I ask a stranger to handle the boar -- literally to put their hands on the boar, with me right there. That's the final step of the vet visit... or the farm kill visit. You want the animal to be used to occasional strangers, and to know that as part of the routine.
I work with each of our sows in the same way, and make a point of touching then and talking to them on my daily welfare checks. That way, when i need to go out a dead piglet, or crawl into a shelter to check a pig they're used to my presence and accept it without complaint.
9 hours ago