My 1 year-old labrador is driving me crazy with this behavior:

In the house or in the backyard, she tends to pick up anything that she can.
Anything except her toys! When i approach her, saying "No" or "Let go", she
runs away, in what seems a playful behavior. I try raising my voice, to show
her i'm not playing, but it doesnt work. She hides from me. I have to take
her in a corner so that she let the object go.
I've also tried "trading" : showing her a toy (Kong or Ball) that she can chew.
But with no success. She prefers the forbidden.
When i catch her, i dont know what to do. Reward her to finally let it go? Punish her?
Has anyone a solution?
Thanks in advance...
Raising your voice does no good.
Chasing her will make her do the opposite of what you want - don't chase her.
Don't punish her, that does no good.
What WILL work...
1st - Professional obedience training. This will train you as well.

2nd - After learning how to train your dog, the tools at your disposal are...
-Your attitude (YOU are the boss PERIOD) chewing on anything other than her toys is not permitted EVER!
-The word NO! This will only work when you catch her in the act. Say NO!, then stop her from chewing wrong thing, and place one of her toys in her mouth, then say GOOD DOGGIE!. Saying NO! is useless 10 seconds after the act. It must be WHILE she is doing something wrong.

-A leash and training collar. Learn about this at obedience training. Take her around house/yard and give her opportunities to chew on wrong thing. Say NO! and correct her with leash (when chewing on wrong thing), give her a dog chewy/toy, then say Good Doggie! (NO! when chewing on wrong thing, GOOD DOGGIE! when chewing on right thing.) This can take weeks and lots of patience.
-Dog repellant spray. Spray anything she should not chew on.

-Anything else which would not taste good to the dog or would be unpleasant for the dog like some types of noise making devices. Associate these things (in her mind) with her act of chewing on wrong things.

But keep in mind it is natural for dogs to chew. And chew and chew and chew. Therefore it is unreasonable to expect the dog to not chew on anything. The idea is to get the dog to "switch" to dog chews/toys. So have plenty around for her to chew on. I have several in each room of my house as well as outside.
My dog has no reason to chew on anything else. There are plenty of her chews available everywhere! I must have about 40 of these scattered around. My house/yard looks like a "mine field" of chew toys! But I would rather have this than her chewing up my stuff - some of which is dangerous (electrical cords) and other which is valuable.
And I have so many electrical cords, I just had to learn how to keep her away from these. (For her own safety.)
Then the idea is to make it "unpleasant" when the dog chews on the wrong thing - dog repellent, saying NO!, leash correction, etc. Then VERY important to praise dog when she is chewing on the right thing. GOOD DOGGIE, etc.
Then you MUST be consistent! If sometimes you say NO!, then allow her to chew on wrong thing, you have wasted your time. NO! means NO! PERIOD! Each time, every time.
Over a period of time and being consistent, the dog will see it is "unpleasant" to chew on wrong things. That she is rewarded for chewing on right things. After several weeks - maybe months, she will look at wrong thing = "Humm - Not fun to chew!", then right thing "Hummm - Fun to chew!"

It is easier if you can be there at all times and follow her around constantly. She will learn quicker. If you have to be gone and can't do this, ask professional trainer what to do during training period for your specific situation.
Good luck! It is actually quite easy to train a dog. It is just a matter of "communicating" to the dog what is wrong and what is right. Think of this like a small child. You have to tell them over and over!

P.S. Don't have any dog chews which are anything like things you don't want the dog to chew on. A dog does not know the difference between an old sock and a new one. Or an old shoe and a new shoe.
My 1 year-old labrador is driving me crazy with this behavior: In the house or in the backyard, she tends ... behavior. I try raising my voice, to show her i'm not playing, but it doesnt work. She hides from me.

Wouldn't you try to hide from someone who yells at you?
I have to take her in a corner so that she let the object go.

The first thing you need to do is remind yourself that you have a RETRIEVER. Retrievers love to RETRIEVE things, provided they have someone to throw things for them to RETRIEVE. If they don't, they'll find "things" to retrieve by themselves.
All you ever do is take things away from her. Where's the fun in that?
Instead of "taking her in a corner," just THROW something else for her to RETRIEVE. She'll likely drop whatever she has in her mouth and take off to RETRIEVE the new "thing."
Don't worry if she doesn't initially bring it all the way back to you. You can teach her to do that later on.
Buy a couple (or more) dummies (very good "things" for your dog to retrieve), like these:
http://www.gundogsupply.com / 9645.html
Or you can offer her a favorite treat. She'll probably drop the toy to get her treat.
But you NEVER, EVER want to struggle with her, or play tug-of-war.
I've also tried "trading" : showing her to get a toy (Kong or Ball) that she can chew. But with no success. She prefers the forbidden.

Until she learns what belongs to her, and what doesn't, put up all the other stuff so that she can't get to it.
Then spend some time every day throwing dummies for her.

Tease her with the dummy, get her all excited, leaping, etc., then give it a toss. When she gets it, and starts to come near you, toss another one. Rinse. Lather. Repeat.
When i catch her, i dont know what to do.

First, NEVER, EVER chase her when she's got something in her mouth.

Second, OBEDIENCE TRAINING will make it possible for you to call her to your side. No "chasing" required!
Reward her to finally let it go?

Yes!
By tossing something else for her to retrieve, offering her a special treat, etc.
Punish her?

For not coming when called? For not releasing the object?

No.
Has anyone a solution?

OBEDIENCE TRAINING.
Usually in the form of a group class.
It will help you regain control of her.
Your vet can usually aim you in the right direction, or you can call your local animal shelters, rescues, too.
They will be able to teach you* how to teach your *dog a more formal retrieve, too, which will give both you and your dog countless hours and opportunities for fun and exercise.
Good luck!

Handsome Jack Morrison
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When i catch her, i dont know what to do. Reward her to finally let it go? Punish her?[/nq]If you punish her when you catch her, expect the problem of her running from you to get worse instead of better. She also will be less likely to give things up to you if punishment is what follows. I have a rule that I lavish my dogs with praise when they give me something or drop it whether they do it right when I command or when I make them. For example, puppy has a sock in its mouth. I tell puppy to drop it. Puppy doesn't drop it. I go to puppy and tell puppy to drop it again, this time making sure that the dog lets go of the sock.

As soon as teeth are off the sock, I say, "Good drop it!! Good dog!!!" and give him a much loved belly rub. Dog learns that what I want when I say drop it is to let go of the object and that he will be rewarded for doing so. If I yelled at him while going through the process, he'd learn to avoid me when I told him to drop something. As it is, he learns to drop the object happily and run to me to get a belly rub. There still may be things that he doesn't want to drop, but at least I haven't made him leery of dropping anything or being anywhere near me when I tell him to drop something.

Paula
"Anyway, other people are weird, but sometimes they have candy, so it's best to try to get along with them." Joe Bay
For example, puppy has a sock in its mouth. I tell puppy to drop it. Puppy doesn't drop it. I ... I say drop it is to let go of the object and that he will be rewarded for doing so.

Since this is a LAB, I would be asking her to BRING me anything she picked up. May as well teach her good retrieving skills along with drop it or give!
I've had young retrievers bring me TP, shoes, coins, wrappers, all sorts of stuff. They've never run with it, because I always ask them to bring it in a very happy voice, praise them and engage them with an appropriate toy. Picking stuff up is often a bid for "you gotta get off the computer and play some fetch with me". Doesn't always happen, and not always immediately, but I have dogs who bring me stuff. Rudy often has some interesting things in his mouth, but they all get brought.

Janet Boss
www.bestfriendsdogobedience.com
For example, puppy has a sock in its mouth. I ... object and that he will be rewarded for doing so.

Since this is a LAB, I would be asking her to BRING me anything she picked up. May as well teach her good retrieving skills along with drop it or give!

Watch out for the monster you might create when you teach a lab to bring you stuff. You can end up with the entire contents of your house in the one room you are in once they figure out how fun that game is. You gotta love goofy labs and their eager to please especially when it's fun attitude. If I tell my dogs to give something to me and I'm not right there, they bring it to me. But I'm not sure how I got there. Never really thought about differentiating. I just do drop and give it to me and it turns out that way. I haven't wanted it any different way, so I've never thought beyond that.

I have seen the utility of a drop command from a distance. I tell Scooter to drop things from the other room all the time. I hear what sounds like getting into trouble, tell him to drop it and in he runs for his reward. The kids like to go see what he was getting into when I do that. It is almost always something of theirs that he is into. I don't leave things out where I'm not able to supervise them. I figure I'm training my kids along with the dog.

Paula
"Anyway, other people are weird, but sometimes they have candy, so it's best to try to get along with them." Joe Bay
Watch out for the monster you might create when you teach a lab to bring you stuff. You can end ... me and it turns out that way. I haven't wanted it any different way, so I've never thought beyond that.

When Franklin (one of them long-haired labs!) was a puppy, I had a pile of shoes next to my computer desk. He particularly liked to get a big drink of water and then pick up one of my rubber garden clogs (which were kept right next to the water and back door). At least they were easy to drive!
If I could (or would) channel Rudy's coin collecting habit into getting money from outside of the house, I could have a real racket (sp?) going!

Janet Boss
www.bestfriendsdogobedience.com