The biting is not a behaviour problem

Every puppy bites. Your hands, your sleeves, the children, the back of your legs while you walk. It is not aggression, it is not a temperament warning, and it does resolve.

What people are not told is that a good proportion of the worst biting is being generated by the household, accidentally, several times a day.

The three amplifiers

Tiredness. This is the big one and almost nobody believes it the first time. A puppy who has been awake for two hours is not a puppy who needs more exercise. That is an overtired puppy, and the biting is what overtired looks like in a dog.

Puppies need somewhere between eighteen and twenty hours of sleep a day. Most puppies in busy houses get nowhere near it, because every time they settle somebody walks past and they get up again.

Hands as toys. Somebody in the house is play wrestling with their hands. There always is. They enjoy it, the puppy enjoys it, and then the puppy applies the same rules to the four year old's face.

Pulling away. When teeth land, the human instinct is to snatch the hand back fast. That is exactly what prey does, and it makes the hand ten times more interesting. Slow is boring. Fast is a game.

Fix sleep, take hands out of play, and stop snatching. That is most of it, and none of it is training the puppy.

What to actually do when teeth land

Go still and boring. No noise, no yelping, no correction. Hand goes limp, eyes go elsewhere.

Then redirect onto something legal that moves. A toy on a rope is better than a toy in your hand, because it separates your hand from the fun.

If it escalates, the puppy is over tired and the answer is not more play. It is the crate or the pen, with something to chew, and a closed door. Not as punishment. As sleep.

Most people find out within three days that eighty percent of the biting was a sleep problem wearing a costume.

What not to do

Do not hold the mouth shut. Do not scruff. Do not put your thumb under the tongue or any of the other things that circulate. They all teach a puppy that hands near the face are unpleasant, and you will need that puppy to accept hands near their face for the next fourteen years, at the vet, with a foxtail, with a tick.

The short term win is not worth what it costs later.

Timeline

Worst between ten and sixteen weeks. Noticeably better once the adult teeth are through, around five to six months.

If it is still happening hard at seven months, that is not teething and it is worth a conversation. Usually it is a dog who never got taught an off switch and is now large enough that it matters.

One more thing

The children will get bitten. Not because your puppy is dangerous, because children move fast and squeak.

Do not solve that by telling the children to be gentle. Solve it with a gate. The puppy and the children get supervised access in short blocks and separate the rest of the time. It feels excessive for about a week and then everyone is happier, including the puppy.