Bite inhibition is how hard to bite not "just dont bite". A dog should already have bite inhibition when it leaves its mother and siblings. There was a dog in my first obedience class that never learned and he would just bite as hard as he could on any of the dogs whenever. Just playing(his version of it) he put a hole in another dogs ear. They kicked him out of the class and I dont think the lady ever took him to a behaviorist.
this is not normal behavior if the pup has no bite inhibition. If it does then its no big deal,but it sounds like the pup was taken to early. A dog with no bite inhibition will always bite to hard or to much. That means no playing with other dogs because why is it fare to them to get bit that hard. It is in no way the pups fault though. It just never learned. You'd also never want it around kids. Kids and dogs play but this dog won't understand how hard it is chewing or biting.
You can not just teach this dog to never put its mouth on anything. There will be times when it wants to play and it needs to learn how much is to much. I really wish the first trainer i worked with had a website but I don't even think I have the guys number anymore. I did hear recently that some shelters automatically euthenize pups taken too early though because of it. It is not a little deal.
"Any dog, no matter how stable of temperament, can be pushed into a
position where they feel they must bite to defend themselves. The
difference between the dog that administers a good hard pinch to the
tormenting six year old human and the dog that rips the six year
old's face off is bite inhibition."
http://www.shirleychong.com/keepers/archives/bite.txt
Another website says it needs learned by four months but every trainer or behaviorist I've talked to said before leaving the mom.
"A dog's ability to control the force of his biting is called "bite inhibition." It's a critically important skill that every puppy needs to learn, the earlier the better. At first, they don't know their own strength nor how sharp their little teeth really are. Puppies learn to control the force of their biting from the reactions of their mothers and littermates during play and especially play-fighting."
http://www.canismajor.com/dog/bite2.html
A lot of these are just the yelp and back away but that did not work with my husky. If it works for you great,but just find something that works