Also in some cases, I've heard people hunt hog with them?? I have an AR so would it be possible to hunt larger game with a quick 2 or 3 shot on them?
Yeah, people hunt hogs with .223/5.56 AR15s. They also hunt them with .22 lr and .17 hmr. As noted above, the notion of getting multiple shots into an animal is faulty, though I don't believe it is necessarily unsportsmanlike or inhumane.
I can't think of any hogs that I have shot over the years that didn't take off like a bat out of hell, if they still had the ability to run, after being shot. I can't think of anyone that I have seen shooting fast with an AR15 .223/5.56 that was able to place rapid fire follow-up shots anywhere remotely close to being on target within being less than 10 yards away.
The problem with .223/5.56 isn't that it won't kill. The problems with the caliber have more to do with the shooter's training abilities and the speed of the kill. Too many hunters go with the "pie plate kill zone" theory and simply expect the hog or deer to fall over if their round hits anywhere in that area. If you don't hit CNS, don't expect a hog to be stopped. It will run. How far it runs is determined by how much damage was done to critical structures. Being small, the .223 caliber doesn't do a whole bunch of damage, so it behooves the shooter to know hog anatomy and to be able to not just place the shot on the outside of the body, but to know where to aim on the outside of the body to hit critical structures inside of the body. Too many hunters are not good at this.
Bottom line, if you use this caliber, choose a good penetrating and expanding ammunition. When possible, focus on CNS shots to the cranium, through the neck into the cranium, or heart/lung shots that miss the humerus (upper arm bone). If the latter, plan on tracking the hog and know that many hogs seal up after being shot, particularly with itty bitty calibers, and don't leave good blood trails.
Suggested bullet? Barnes all copper TSX 62 gr.
However, my real suggestion would be to get another upper in a larger caliber that will produce better terminal results. I like 6.5 Grendel, but there are many other calibers that will work very well and all are going to be better than .223.