Thinking about it, I've been real fortunate in that department, the only time I actually hit one, got er slowed enough, ended up bumping it and she ran off, no worse than before it happened.
I've seen a few doing cartwheels on the highway after being hit multiple times, for some reason one of those multi hits still sticks in my mind, kind of a graphic memory I'd like to forget. Seen one with 4 broken legs, still trying to make a go of it, had nothing to use to end the suffering, + all the countless others I've seen, they sure are one tough and motivated animal.
I recall one, probably 20 years ago, 2 lane road, was driving a tri-axle dump, loaded and climbing an incline, small buck darted out, I narrowly missed it, and never missed a beat or had any time to react to it, as soon as it crossed into the next lane, it put it's head down and head butted the driver side door, knocked the mirror off, nice dent in the door, and fell off to the side of the road, over the white line, after the hit, still can't recall how it got across that lane after a hit like that, but it did. I stopped, person in the car I knew from high school, kind of odd, took the shovel from the dump body and proceeded to take a look, thought it might have been knocked out, but it was dead, had no way to carry it, off the side of the dump body would have drawn too much attention, meat was unscathed, on the return trip after dumping off, it was already gone.