In my opinion, it is reasonable to allow dogs to release this instinctive need if they are cued by stimuli such as people or pets in their territory.
However a controlled amount of barking should then be halted with a cue from the owner, such as "quiet". If you wish to give this cue yourself, remember to do it in a calm voice at a normal speech level, as shouting "quiet" will be an invitation for the dog's barking to heighten because you are now "barking" with them - game begun.
If this barking is happening while your neighbours are away at work, the simple fact is they will not know the dog is behaving in this way and are unable to correct the behaviour because they are not home at the time.
Take note of when the dog barks and for how long. Be aware that this behaviour does have both visual and sound stimuli.
A loud bang may startle a dog and cause an alarm bark, a visual may be the cause, or you may feel - after looking at the behaviour with fresh eyes, eliminating stimului - that boredom is the cause.
In most cases I deal with, blocking a visual point often resolves the situation, so if you are able to give your neighbour a clear idea of what is happening over a coffee or back fence chat, you will be able to work together to resolve the issue to a point you are happy with.
Paw point of the week
Remember, your neighbour's dog may also help you one day. This has been proven in our own backyard with the alert from our dog coming as soon as our neighbour's window was smashed, preventing any property being removed. Good boy.
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