Q. My friends have two Huskies/wolf mixes and a very small yard. The dogs bark constantly while my friends are at work so they can't catch the dogs in the act. The neighbors are starting to complain. What pet barking devices should they use?
A. Leaving aside for the moment the ethical concerns raised by keeping wolf hybrids as companions, in a perfect world your friends should be more responsible with their dogs. I do not think it is fair to the neighbors or dogs that they are left out all day alone.
How much exercise are these dogs getting? What training has been done with them, or are they left in a doggy gulag 24/7? If these dogs are out all the time, receive little or no exercise (by the owner) or training, correcting the barking will force the dogs into other behaviors such as digging and chewing. Dogs need both physical and mental stimulation to be well adjusted. It appears these dogs are receiving little if any of both.
Citronella anti-bark collars work well, but if the dogs' basic needs are not being met, the collar will mask their stress and unhappiness. What do the dogs have in their "environment" that enriches it or at least peeks their interest? Try using chew toys and toys in which you can insert treats to keep the dogs occupied and quiet. Teach them tricks and agility, basic obedience training.
What about installing a dog door so they have access to the house? Daily exercise or hard running for an hour each day will have considerable impact on their behavior.
I think most people are well-intentioned, and life is busy for all of us. Think of it from the dogs' perspective: They're contained in a small yard with no exercise with little stimulation or direction. You, too, would eventually become pretty verbal just to break up the boredom.
In short, bring the dogs into the house or install a dog door. Make sure the dogs have toys and objects to keep them occupied. Start exercising and training them. Then use the citronella collars if barking remains a problem.