I spoke with a hunting buddy of mine about hitting pigs, deer, etc. He is a tool man that services various auto and autobody shops. I then looked at information from a variety of news sources online. This is what I came up with (with his help).
According to his sources, the average cost for a person to hit a hog on a FM road or highway STARTS at about $1250 and goes all the way up to totaled. Some of the biggest expenses for even seemingly minor hits are airbag replacement because of airbag deployment during the collision.
The nice thing about hitting hogs over hitting deer is that if you just strike the animal, chances are that injury to the human occupants of the vehicle tend to be minor and often people are uninjured aside from the shock of the accident. As hogs are low down to the ground, the damage on the vehicle tends to be low as well. Vehicles still may be totaled, but because the damage is low, the vehicle absorbs most or all of the impact without involving the passenger compartment. Some of the most common injuries resulting from striking hogs were injuries from the airbags hitting the human occupants. In short, hogs tend to be hit from the grill and lower. As such, there is often lower bodywork, steering, engine, and frame damage that may commonly occur
Deer tend to be hit from the grill and higher. While most people are similarly uninjured or only suffer minor injuries from striking deer, because of their longer legs, leaping as they run, etc. deer impact higher on the car and can come through the passenger compartment through the windshield. This often results in serious injuries and sometimes in death. As deer can be at multiple elevations, you can have much of the same damage as with hogs, but generally it tends to be higher up. So a glancing blow of a deer up high on the passenger side may take out your headlight, quarter panel, and related body work, but down lower, when hitting a hog you end up with bumper, frame, quarter panel, and steering issues.
Those are all sort of generalities, but you get the idea that hitting a big heavy object down low can do nasty things to your vehicle, though you may be fairly safe. Hitting deer higher up may or may not do as much damage, but different damage, and if one animal is going to kill you, it will be the deer coming through the windshield.
Hitting a hog or a deer virtually never causes your vehicle to roll over. In every case that I found where either animal was struck and there was a subsequent rollover, the rollover occurred because control of the vehicle was lost and the vehicle (most often) left the roadway such as by entering a ditch or field where the wheel caught that resulted in the rollover. I do not doubt that airbag deployment was a contributing factor to the loss of control Several of the rollovers occurred without the vehicles ever striking the animals, but were again the result of a loss of control of the vehicle, usually during or after a significant swerve at higher speeds, resulting in going off road or hitting some sort of stationary object such as guard rail pylons. Rollovers often produce serious injuries at highway speeds.