Shock collars are an aversive training device. According to the Humane Society of the United States:
"They suppress the unwanted behavior, but they don't teach him what the proper behavior is. At best, they are unpleasant for your dog, and at worst, they may cause your dog to act aggressively and even bite you."
Some people call them "Bark Collars" but, barking collars don't bark and aren't only used to stop dogs from barking. They are shock collars. Calling them something different doesn’t change what they are. Their sole purpose is not to train but to punish undesirable behavior with pain.
Stop and think. If you have taken a dog into your life, you have made a silent promise to love and care for it for its lifetime. Is that how you treat someone you love? What would be your thought if a loved one sent a jolt of electricity through you every time you did something they didn’t like?
Some proponents of shock collars suggest that associating barking with getting zapped teaches dogs to repent. Barking is not a sin. It is, in fact, a trait bred into dogs by humans. Dogs don’t sin. Their owners do. Full stop.
The only way to have a happy, well-balanced companion is to set him/her up for success, not failure. It takes a little more effort but results in a more substantial reward. Redirect undesirable behaviors into acceptable behaviors and reward for success. People for the Ethical Treatment of Animals (PETA) says:
"Dogs wearing shock collars can suffer from physical pain and injury (ranging from burns to cardiac fibrillation) and psychological stress, including severe anxiety and displaced aggression. The anxiety and confusion caused by repeated shocks can lead to changes in the heart and respiration rate or gastrointestinal disorders."
I know this is true because I have seen it in two very different dogs.
A Bichon Frise in our neighborhood has a shock collar. When she is wearing the collar it is pitiful. She whines softly as if afraid of being too loud. It is beyond me why her family wants to inspire fear in that sweet little dog. The days when the collar is off, she barks her little head off. In my heart, I cheer her on every time I hear her. I've noticed that lately the collar is off more than it is on. Maybe they are figuring out it doesn't work.
A black lab puppy started attending our weekly dog social a while back. After a month or two, its guardian decided to add a shock collar to its training. Whenever the dog didn’t do exactly what was expected as quickly as expected, she would shock it. This dog that had gotten along well with all the other dogs turned aggressive within a month and we had no choice but to ask her to remove her dog from our group. I only wish she had broken a law so I could report her to the authorities.
If I had my way, shock collars would be removed from the market. Although these devices come with a range of settings that I have heard described as "from a tickle to a jolt," as long as there are settings that are greater than “a tickle” there will be morons who will use them to torture dogs or other pets. There is no reason to use them when positive training methods yield much better results. The ASPCA also has an excellent article on why our dogs bark and what we can do to quiet them.