ANY tool can be a crutch, and you can become dependent on them. Tools do not train dogs - people train dogs. Headcollars (I use the Gentle Leader) can be very good management tools - what I mean by management is that you can use them to immediately gain control of your dog while you begin to train new behaviors to take the place of the old unwanted behaviors. The headcollar can give you the appearance of a trained dog because in many dogs, you see an immediate cessation or lessening of the behavior - but as soon as the headcollar is off, the old behavior pops up again. So the key really is to have a training plan in place while you are using the headcollar and decide how you will eventually wean the dog off the collar. Now, some people are very happy with the results they get from the headcollar, and just use the headcollar forever - same way you see some people using chokes or prongs indefinitely.
Headcollars MUST be used appropriately. I advise anyone who is going to use one to try to find someone who can give them a training lesson using one, instead of just reading a book or getting advice online - because it really helps to have someone show you IN PERSON what the appropriate fit is supposed to be, how to condition the dog to it, and how to position the collar, handle the leash when the dog is in the collar, and so on.
As for aggression, yes, in some cases the headcollar is very useful, especially for safety and control with dogs who are otherwise difficult for their owners to handle.
Here is the content of my headcollars handout:
The Head Collar
The head collar is of great use on dogs with aggression and/or fear issues, or simply on over-exuberant dogs that just don't seem to understand that the human on the end of the leash is the one that should be calling the shots. The design of the collar allows for maximum, yet gentle control of the dog's head and muzzle, with the nose loop simulating the authoritative yet calming "muzzle grab" dogs often use on other members of a canine social system. A second strap around the back of the neck applies controlling pressure. That means there's no pressure applied to the throat. The result: instant, humane management of even the most unruly of dogs.
I use and recommends ONLY the Gentle Leader brand head collar. I have found this to be the most useful of the head collars, and best-fitting.
Introducing your dog to the head collar: When properly introduced, most dogs adjust fairly quickly to the new and unique feel of a head collar. Patience and praise are important during the adjustment phase. Remember, your dog does not understand what is going on and needs your reassurance and guidance. To you it’s "just a head collar", but for your dog, it could seem like a potentially dangerous, frightening contraption. For this reason, please be sure to follow the below instructions carefully:
1) The first time you introduce your dog to the head collar, make sure the experience is as pleasurable as possible. A quiet area of the house is the best place to work, when your dog is in a relaxed mood. Have a bowl of especially yummy treats handy (you will use these to reward and encourage your dog).
2) Be sure you've read and fully understand the instructions that come with the head collar before you actually place it on your dog's head.
3) Use a regular collar with a leash attached to it, in addition to the head collar with another leash attached to that. If your dog becomes upset or acts up when you first place the head collar on his face, you will use the regular collar and leash to help steady and restrain him. THIS IS IMPORTANT!
4) Allow your dog to sniff the collar. Rub it over his face gently. To help your dog relax, rub behind his ears and the back of his neck. Slip the muzzle loop over his nose, and as you do, slip him one of those yummy treats. Buckle the straps that fit behind the ears/on the back of the neck. Be sure the collar is secure and fitted properly: you do not want it to slip off or have your dog paw it off. Give your dog another treat.
5) Gently guide your dog around the room. If he doesn't willingly follow, use a happy, upbeat voice, encourage him with the food rewards and guide him with the buckle collar and leash. If he attempts to paw the collar off his face, use the buckle collar to hold his head up. As soon as he stops pawing and/or begins to follow you, reward with a food treat.
6) Some dogs will freeze up when the head collar is first used. These dogs need firm, yet gentle and encouraging guidance, and should be rewarded with a treat AS SOON AS THEY SHOW SIGNS OF FORWARD MOTION.
7) Ask your dog to perform a few commands that he already knows while in the head collar. If he does not respond, gently guide him into position and then reward.
8) Make a big fuss over the collar, act happy and upbeat. Try to get your dog excited and "acting normal". The goal is to get the dog to accept the head collar as well as his regular buckle collar.
9) For the dog that is putting up a huge fight, get him into a sit position, then reward for sitting quietly. Even if this is the ONLY thing you can get your dog to do at the moment, don't worry about it! You need to gradually let the dog become accustomed to the new feel of the head collar. As he becomes more used to it, you can begin to ask for more behaviors and movement.
Remember: do NOT let the dog paw his way out of the collar. Use both the buckle collar and SOFT PRESSURE with the head collar to help restrain him, then reward, reward, reward for calm, quiet behavior.
10) To further help your dog adjust, save the really special treats just for when he's wearing the head collar. Is there something your dog goes bonkers over but isn't allowed to have on a regular basis? Use it for head collar training sessions! The idea is to teach the dog that the head collar signals GOOD things are on the way.
11) Once your dog seems adjusted to the collar and you have control over him around the house, take him out into the backyard, then the front yard and finally out for a walk in the collar. Keep the second leash and buckle collar on him to be on the safe side. After you've been using the head collar and you both feel comfortable with it, you can remove the other leash and collar. I do, however, recommend that a backup collar always be worn. The leash can be attached to both the head collar and the backup collar with the use of a “coupler” (ask your local pet store about this piece of equipment that is usually meant for walking two dogs with one leash).
Dos and don'ts of head collar use:
DO keep a loose leash when your dog is in a head collar. The only time the leash should be tight is when you are using gentle pressure to guide your dog.
DO reward your dog consistently for GOOD behavior while he is in the head collar. The head collar allows for good control, but to ensure your dog learns how to behave when the head collar is off, it is important to REINFORCE the good behavior so he knows to repeat it.
DO use the head collar for all walks/desensitization sessions. The reason the head collar works so well is because it instantly stops bad behavior and allows for new, GOOD behavior to be reinforced. Until your dog learns to properly behave, keep using the head collar with lots of reinforcement. Remember, you need to break that cycle of bad behavior for new behavior to take its place.
DON'T leave the head collar on your dog when he is unattended.
DON'T let your dog paw off the collar. Once he learns he can escape from the collar, he'll keep trying.
DON'T ever jerk the leash when your dog is in a head collar. Doing so could damage the neck and spine. ONLY gentle, guiding pulls and pulse-and-release pressure should be used. THIS IS SUPER IMPORTANT!
DON'T let your dog dash to the end of the leash when he is wearing a head collar, and do not suddenly stop short, allowing your dog to hit the end of the leash and then snap his neck to the side. Always use gentle guidance to let your dog know what you are about to do. To stop forward pulling motion, you may slowly stop and then allow the pressure on the leash to stop your dog as his head is pulled gently to the side, but remember, you do NOT want to use any sort of jerking motion; doing so could injure your dog's neck.
For more information on the head collar, go to:
www.gentleleader.com© Mary Harwelik
I look forward to learning much here