There are 2 forms of biting, and I can't tell from your question which problem it is. Biting is aa natural way for puppies to play. This in not as big of a problem as the aggressive biting, but still needs to be corrected. In the aggressive biting, the dog will have its nose wrinkled up and make quick snaps, along with low growls. In both cases, you need to take over as top dog and quickly correct it every time it bites for whatever reason. It is confused about who is in charge. It is quite possible it is used tobeing in charge, and intends to stay in charge. Likely it is already neutered,but do so now if not. Dogs with behavior problems should never be bred. Then
You need to take over as top dog. Having a good pack structure reduces such problems. The dogs see all the
People and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack
Members outrank the 4 legged ones. You can learn to play the role of top dog by
Reading some books or going to a good obedience class. A good obedience class or book is about you learning to be top dog, not the dog learning it gets a treat if it sits. Start at
http://www.dogsbestfriend.com/.
Young Labs, which I know best, and other puppies tend to very bad about
Biting. You see a litter of them, and all the ones that are awake are biting another one or themselves. I am not even sure they realize that when they are
Alone, if they quit biting, they would quit being bitten. At 3 to 4 months they are getting their adult teeth, and it seems they spend every waking moment biting or chewing. I maintain a Lab's favorite chew toy is another Lab. Otherwise they settle for any person they can. They keep
Hoping to findone that won't yelp and jerk their hand away, or growl "Bad dog." and clamp their mouth shut. Then offer a chew toy. They keep trying despite hundreds
Of corrections. Another good technique is to quit playing and go away. Besure to praise them when they are playing nice and not biting.
You just have to keep on correcting them, hundreds of times, not dozens.Provide sturdy, safe toys such as Kongs and Nylabones. Avoid things they can
Chew pieces off and choke on them. Keep them away from electrical cords.Crates are essential for most young Labs and other dogs.
You need more help than I have here. Unfortunately Askme Help desk is limiting me on how long my answer can be. I am going to submit this and see if I can add more. You may need to submit another question.