Getting my parents' dogs to shut the hell up

ChopperDave

These are my parents' dogs.

D'awwww.

They're adorable, but lately they've developed a penchant for barking. A lot.

If left to their own devices, they will sit vigilantly by the door pictured (or the one in the same place downstairs) and just bark, at anything and everything. Joggers. Other pets. Squirrels. Leaves. Tree branches moving in the wind. Shadows. Sometimes I think they hear other dogs barking down the street and bark in response, though we're the only ones who hear them.

We used to just keep them away from the doors, but that doesn't seem to be working anymore. First of all, there are doors and windows everywhere in my house. Second, the dogs have taken to barking in the middle of the house at NOTHING (probably other dogs they hear but we don't).

So aside from hovering over them and pinching them / squirting them with water / rattling a penny can every time they bark, what the hell can I do to stop them?

Has anyone used one of these Dog Silencer thingies? Do they actually work? Worth the price?

HK5

I've had good luck with my dog using a citronella collar. It doesn't eliminate barking completely but he's learned that he can only bark under the level that sets off the collar, which is very tolerably quiet. It's also reduced his overall frequency of barking by about 75% and replaced it with some pretty humorous muttering noises he makes that sounds like an old man grumbling.

Added bonus that if he does bark, I get the sweet smell of lemons as a consolation prize. I bring him to work with me and he's basically my little air freshener.