You can definitely shoot them, but you can’t “hunt” them, per se. Also you can’t really rely on them for sustenance, unless you’re a Rockbiter from The Neverending Story. And those guys are a totally effed up species, because they’re essentially eating themselves to survive. It’s like if you just sat there munching on random people’s arms all day long. Additionally, you have to simply stay put as the Nothing comes and destroys everything, because you’re too slow and too busy being ravenous for arms to escape. Long story short, don't shoot the rocks.
Much like the squirrels, they provide a scant amount of meat, but they’re much dart-ier. What the rabbit lacks in pounds, it makes up for in raw challenge -- you know you’re the kind of Oregon Trailer who’s become totally distracted from getting to Oregon and totally addicted to hunting when you can wait for these varmints to pop onto the screen, then use the advanced move of working your Apple II’s number pad to spin around and pop them.
These suckers are huge, and will give you wayyyy more meat than you can carry back to the wagon, but they barely move, taking all the sport out of the damn thing. And you definitely abandoned your lucrative banking job in Independence, Missouri for the sport.