Cowa, I'm posting this as a comment instead of an answer, because it's
tough to give a complete behavioral solution over a forum like this
(without having met or seen the dog, for example). That said, here
are the thoughts of my dog trainer partner:
Like any form of re-training an unwanted behavior, the approach is
multi-pronged. But the answers require more information.
Where does he eat, play, sleep, and is he in the yard for long periods
alone (because you mention chewing the handles in half - that takes
You pay attention to those things, you spend time with them, they have
your interest. So they have his interest.
If you EVER laughed at it - you helped create it. Laughter is great
praise. What's adorable in a puppy is often no fun once they grow up.
Essentially to undo something you've done you apply a few simple
concepts. Your first goal is prevention. You need to make sure the
dog can't get at those things while you are not ready and available to
work on retraining.
Chewing is related often to a three headed problem: boredom, stress or
inadequate exercise. Any combination of those things create in a dog
the desire to relieve stress by chewing. Many breeds need more than
the average exercise available in walkies.
Be glad he's after your tools not your landscaping you would NOT
BELIEVE the amount of damage a dedicated chewer can do to trees,
bushes and decks in an afternoon.
So prevention first. Access with supervision is next.
There are two new commands you need to work on, three if you're up for
it. First: "Leave it." Essentially, "leave that alone - turn your
head away." It's an alternative incompatible behavior... That's
trainer for dog can't do TWO things at the same time. Leave it - can
not be done at the same time that the dog is CHEWING.
Another handy one is to focus on you - totally - when you say "Watch
Me." Dog looks at you, bingo you pay off with treat/toy AND praise.
A dog holding another object in it's mouth - Hold It, is not chewing another thing.
To start with the behaviors you do have in place. Since you say you've
been training him all along - you should have solid sit, stay, down,
come. Take him out on a long line - some soft braided nylon at least
1/4 inch thick, any thinner and you risk cutting your hands. Let him
drag 10-15 feet of line with him. If he starts reacting to your
stuff, pick up the line and do some heeling and brief sits, downs,
make him work, REWARD him well but do it all at a good pace. Then
release him and go back to your work.
Depending on his down/stay duration you can also alternate with
periodic long down/stays when he messes with your stuff. Don't get
angry, don't feed into any stress. Just put him in a down stay in a
shady spot and make it stick.
If you haven't developed solid sit stays and down stays as part of
your practice you need to do that, they're about leadership as well as
If every time he pays attention to your stuff he is put to work, he's
going to rethink his strategy in the long run. As modification I
would, without knowing your answers, add extra exercise every single
day and if you walk, get jogging shoes and try that, or a bike and a
"springer" dog attachment, I'd also buy both bitter apple spray and
bitter lime. Sometimes dogs like one or there other but usually not
both. Just as a taste deterrent.
The idea is to take any stress (good or bad doesn't matter) back out
of the situation by stopping corrections, or anger, by providing
additional exercise, by making it taste nasty if you forget and leave
it where he can get it, by providing supervision and training into
doing other things. And give him something to DO out there. Buy a
tetherball set, hang a heavy rubber jolly ball with a handle from it,
and teach him to play. Get a used bike tire from a bike shop, hang it
from your roof joists with a segment of bungee rope and let him tug
himself to tired. Build him a digging pit - digging is wonderful
stress relief for dogs.
Teach him to Watch Me - when his focus shifts where it shouldn't.
Tell him to Leave it - if he's moving that way. Since you have
trained other commands teaching those two should be simple enough.
Dog makes eye contact - good dog! Good Watch Me, REWARD. And work up
from there. Leave it is sometimes called Doggy Zen. To get the
cookie you have to leave the cookie.
Corrections, pushing, shouting, even gruffness are all a form of
attention for an undesired behavior, they will focus some dogs MORE on
the objects not less. As you've found out I think. Some dogs are
just geared that way.
That's why the emphasis is on alternative behaviors. They take the
emphasis off the thing being chewed/guarded/destroyed. It will take
you several more months to untrain it than it took you to TRAIN it.
Dogs love habits, and it sounds like this is a well entrenched one.
Distract by offering him a command he enjoys and knows will be HIGHLY
REWARDING - Leave it or Watch Me - and some wonderful seldom ever
gotten type of cookie (garlic roasted chicken breast, steak bits -
good stuff), prevent when you cannot supervise, offer alternative play
forms for things to do while you use your tools, work on the sit stays
and down stays, provide insane amounts of exercise (a tired dog is a
good dog, I promise).