my puppy is biting to much what do i do??

Question
my 2 and a half month old golden retriever pup is biting to much. when he's  not playing or active he's fine but once he get going and starts running and playing he is a little to rough he bites real hard he also pulls on peoples hair and wont let go unless you open his mouth and take it out we usually say no to him and if he gets to wild he put him in his cage and let him bark so he learns that he's missing out on play time is this the write thing to do or is this normal in all puppies and when will they eventually grow out of this stage?
thank you
Christine

Answer
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.  One thing you can do at that stage is to knot and wet a piece of cloth.  Then freeze it.  The cooling will sooth the gums.  Only let the puppy have it when you are there to watch it.  I maintain a Lab's favorite chew toy 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.  One thing you can do at that stage is to knot and wet a piece of cloth.  Then freeze it.  The cooling will sooth the gums.  Only let the puppy have it when you are there to watch it.  I maintain a Lab's favorite chew toy is another Lab.  Otherwise they settle for any person they can.  They keep hoping to find one 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.   Be
sure to praise them when they are playing nice and not biting.

He will not grow out of it, at least not for a few years.  It will not be quick and easy to train him out of it.  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.