Apparently your dog is bored out of his mind. Mine is still a pup and with lots of stimulation and walks he is not destructive. They are an active breed and thus wanting to play all the time. I suggest that you teach him that nipping is wrong by squealing like a pup when he does, this this teaches him that he is hurting one of his pack members. They also become very vocal when they want to do something. I suggest playing ball, which they love to do, and going on long family walks. This will help out with the frustration he feels, also they do become tired after a hard day of play. If doing so, this dog will become a family oriented dog who loves a lot and wants to please his owners.
hi ya, my amstaff was the same when he was 5 months, and he wasnt nipping the kids out of spite, he just wanted them to play with him, we came through this by the kids caring a toy around when he was at his playfull stage, and also a treat. you dog needs lots of walks and excercise as they are a very active breed, try to get him out at least twice a day, and if you have dog parks near you take himthere, mix hi with as many other dogs as you can and he wil learn the power of hos jaws and that he can hurt, we tried to yelp everytime our puppy knipped but this didnt have much effect it may work with your dog thou1 spend alittle time each day getting him to play nicely with you and the kids and treats when he plays nicely, also teach the kids to train the dog, this helped us . our dog has great respect for my kids now . hope this helps