TBH, I blame the loud dog as the root issue to the problem. Chickens are prey creatures, so a loud predator is going to stress them out. And stressed out chickens make stressed out chicken noises. The alert that they put out for these situations is essential to the survival of the flock, so I wouldn't expect them to stop any time soon if the situation remains stressful.
Would it be possible to put up privacy fencing or bushes to block any line of sight to your chickens, and possibly dampen the noises? These will have the dual effect of reducing the amount of noise that is able to leave your property as well as reducing the overall stress of your chickens and therefore reducing the noise they make to begin with.