Barking is always an issue for people with dogs and neighbors.
Virtually all herding dogs bark in order to move their sheep, horses, cattle, etc. Icelandics are herding dogs. Barking has been bred into them on purpose for hundreds of years. Can you reduce the amount and length of barking? Yes, I believe that you can.
First, don't leave your dog outside alone. She must be "with" you.
Herding dogs like, no love, companionship. You know from experience that your dog loves to be with you. She does not like it when she doesn't know where you are. That's a herding behavior. The herding dogs "need" to be with the herd. They are uncomfortable when they are alone. They like to keep the herd in their vision. Your family is your dog's herd, especially the kids if you have them. She probably ‘watches’ them but would rather be ‘with’ you, right?
Collies, Border Collies, Shelties, Corgis, Briards, German Shepards, etc. all bark. Herding dogs bark more than most breeds, probably. Goldens and Labs retrieve!! Hounds "scent". Greyhounds run. Behavior is genetic. Training can strengthen or reduce behaviors but probably cannot eliminate them completely.
Some people train their dogs to bark. Guard dogs are encouraged to bark. Can you reduce the barking to acceptable levels? Absolutely! If you can train to increase an instinct, you can also train to reduce it.
You must be consistent and ever vigilant especially while your dog is still young. It’s easier to train for acceptable behavior when the dog is still a puppy. It is harder but not impossible to train an older dog.
Some of my Icelandics bark more. Others bark less. It was harder to train my first Icelandic to reduce her barking because I was just starting out. By the time my second dog arrived, I was better. I knew some things to do.
They also seem to bark less as they get older. Everything is new for a young dog. Older dogs have seen more and are less excitable, perhaps.
Puppies are at their most trainable age while still under a year old. That is the time to be firm, but friendly. This is when she is most trainable.
Why do dogs bark?
Almost all dogs bark to warn of approaching strangers, two-legged or four-legged (or winged).
In the case of herding dogs, they bark to move the animals they're herding - sheep, cattle, geese, horses, etc.
Icelandics bark when a human approaches. It is not a hostile bark. Icelandics bark because they absolutely love company! (Icelandics are more likely to bark "on leash" because they cannot get to the person they want to greet. Most folks think that is "bad". It's not. They just cannot stand being separated from a new possible two-legged friend.)
In my yard they bark because they cannot stand squirrels or chipmunks.
Mine bark at helicopters and airplanes, even ones at 30,000 feet, flying overhead. In Iceland they bark at hawks, one of the few natural predators of lambs in the birthing season. (Adult sheep are not prey for hawks because they too big.) I am sure the dogs are barking at planes because their instinct is so strong against hawks. My dogs literally go out the back door looking up at the sky.
I cannot tell you what will work for you to reduce the barking of your dog. Each dog is different. Each owner is different.
I can tell you how I deal with it.
After much work, I have resigned myself to the fact that these dogs will bark. Period. I can reduce and almost eliminate the bark. I can get the barking down to what I am comfortable with. I believe that my dogs are now no worse than the neighbor dogs - except when friends knock on the front door. I am apt to say, "If you don't like dogs, why are you here?" Fortunately all of my friends do like dogs and recognize the barking as a welcome and not as a threat. The bad guys don't know that.
So what are some of the things I've tried?
When my dogs are warning me about a plane, hawk, helicopter, squirrel etc., I praise them. They are doing exactly what they were bred to do. It's in their genes. Trying to punish them for barking won't work. Instead, they may just become neurotic. So when they bark, I praise them. I tell them how good they are. I pet them and scratch them. Then I quiet them. And, this is also important, I also occasionally reward them with a treat - a small dog cookie, etc. after they have stopped barking - immediately after - not in five or ten seconds. Immediately! I have the small cookie hidden and ready to go. I thank them, tell them that they are good, tell them (not yell at them, tell them) "No, bark!" or "Quiet!" and, if they become quiet, IMMEDIATELY, I give them the treat and again tell them good quiet, good no bark, good dog.
Keep a container of Cheerios near the door and use it as a bribe at first to get them to go outside quietly. If they focus on the Cheerios and your “Be quiet!” command, they will be less likely to run out barking.
So, my "conversation" with them would be similar to: "Good girl! "That's a good dog!" "Thank you!" "Thanks for the warning!" all in a calm voice - and then, "OK! That's enough now!", "Let's go inside!" (if we are outside) or "That's very good! Do you want to go outside now?"
I do not leave my dogs alone outside because they could bark. That would not be fair to my neighbors.
I have found that when they are running to the back fence line - the one with the telephone wires that the squirrels walk on - if I whistle, they are more likely to stop barking. They have let me know the squirrels are there. I have let them know that I have heard them. They stop, maybe not immediately, maybe not completely. But they do stop. I often call them back once they have stopped. They are pleased with themselves. They have fulfilled their biological function - protecting me from squirrels.
I tell them, "That's what you get paid for!" "Good dogs." They come back to me wagging their tails. See dad, aren't we good?
I had a big problem with barking and my dogs in obedience school. I strongly encourage all owners of Icies to take obedience training and to continue. It sets you up as the alpha, establishes your control, your credentials as the boss. That's most handy when trying to stop, reduce really, the barking.
Dogs in class do tend to look at and bark at other dogs because they are bored. That ‘play bark’ is an invitation to other dogs to play. If your dog does that, it's because you are not interesting enough.
When you are in class with your dog, you must be the most interesting thing there. Her attention should always be focused on you. How do you do that? Take her favorite toys with you to class and play with them with her. While the boring instructor is droning on and on, practice her ‘tricks’ like sit, down, stay, come, etc. Do it quietly. Dogs do not know the difference between work and play. Make it all seem like play. Doing ‘tricks’ can be play, can't it? As long as she is having a good time, why isn't that play?
While you are playing with your Icelandic, she is ignoring the other dogs. You have become the most interesting thing in class. As long as you are the most interesting thing, she will not bark at the other dogs. (If you are playing with her, she will ignore them.)
Even though I have trained dogs for years, it took an instructor in a class I took to explain another problem and the solution to me.
Recalls are when you call your dog to come to you from across a room (or a field). Whenever I did that my dogs would bark at me. The observant instructor talked me into learning the hand signals. Once the dogs knew the hand signals and I used them instead of my voice, they stopped barking.
The reasoning? I was ‘barking’ at my dogs (the way they saw it) and so they barked back at me. The louder I got, they louder they got. Now I use hand signals and they rarely ever bark in class when I do recalls. If they do, I have to remember to tell them to, "Be quiet!" just before I call them.
I suspect the same thing is happening in the backyard when I tell them NOT to bark at the squirrels or a plane. If I yell at them to stop barking, they yell right back at me.
Instead I try to whistle (or clap) and then use the "Come!" hand signal. That stops at least some of the barking outdoors.
When taking classes, ask the instructor to give you the hand signals for the commands at the same time you learn the voice commands. Use both together until your dog is trained, until it ‘gets it’. Once your dogs focuses on you, the hand signals should suffice.
I find, incidentally, that my dogs learn hand signals much faster than they learn voice commands. Makes sense, doesn't it? They cannot talk, so learning "words" is not natural for them. Dogs watch everything we do. They are learning our body language all the time without our realizing it. They have dog-body-language that they use all the time with other dogs: the play-bow, the tail-wag, the submissive roll-over-on-your back sign, etc.
I noticed my efforts were beginning to pay off when the puppies reached about 10 or 11 months of age. When a dog is younger than that, they will learn quickly but also may forget quickly. You need to reinforce training or they will forget. Puppies are amazingly receptive. If you don't training for barking early, it will be harder to do later.
There is a reason for the phrase "You can't teach an old dog new tricks." It's wrong, of course. It is harder to teach an untrained old dog something new.
Nonetheless, if you develop a great working relationship with your dog when she’s young, you will be amazed at how fast she will learn things even as she gets older. It’s as if they learn ‘how’ to learn and are more receptive as they age to new training. If we ‘grow’ their minds now, we can implant new ideas all their lives. If, on the other hand, we allow their minds to atrophy when young, it will be harder to teach your older dog something new later on.
I can also tell you what I do NOT think will work. Being firm and overly negative will not work. You can catch more flies with honey! Your dog wants desperately to please you. You just need to let her know how she can do that best. If my dogs give a little bark they get attention, positive attention. Then they almost always stop. I do let them bark a little. That is partly what they get paid for.