3 Answers

Put things up where he can not reach them. Get him chew toys and when you catch him chewing something he should not be chewing, take it way and give him the chew toy. Dogs chew out of boredom. Spend more time playing with him or taking him for a walk. 

I have a rottweiler/shepherd mix who is about 8 months old; she chews everything, too. My backyard is nothing but dirt at this point.  I have removed everything  (and she even chews her metal food dish) from the yard and play with her, give her rawhide, and let the other dog spend more time outside than he wants because they play a lot.

As Colleen has already pointed out that that dogs chew out of boredom put all things that the dog tends to chew out of reach walk him/ her a minimum of twice a day they need exercise start throwing a ball with a rope on it and teach him to bring it back this is brilliant for the dog also try and teach him to sit and give paw dogs love to learn always praise him when he does good things never ever hit your dog when you leave the house give him a toy which could be a chew stick and praise him they are intelligent dogs and need one to one talk to him like you would a humane he he is naughty show your disapproval by a loud stern voice and then turn your back on him and don't look at him he will know that you are upset with him this way good luck if you want to know more please don't hesitate to come back we all animal lovers here x