Uhm, if it were only that simple. You think some dogs that are used to human interaction and training are just going to take off and go fend for them selves?
Sad situation. They're obviously a bunch of assholes, with the attention they got from the outdoor show, they should have been able to just give the dogs away to good homes. It takes a sick person to kill that many dogs in a nasty manner. For what it's worth, when livestock is butchered, they don't have some dude crawl down in a hole and shot them, in fact they want the animal to die as peacefully as possible - you excite them, then kill them, and the meat can be ruined from adrenaline...