This is a time of rapid growth for puppies. If you have a highly energetic puppy (and most are), it may seem natural to exercise the puppy as much as possible. However, don’t overdo it—your puppy’s developing bones and muscles aren’t ready to take the strain, especially in larger dog breeds. Repetitive running and jumping are not recommended. I’ve had some clients want to run or bike with their puppy to tire it out, and I always advise them to talk to their vet, as it is not recommended at this age.
Most puppies get the “zoomies” because of all of their energy. This is when they run around the house, sometimes circling a table over and over again, or jumping on and off the furniture. The puppy may even start jumping and play biting you. This usually happens around dinner time, sunset, or right before bed. Clients have called me in alarm when they first get their puppy, as they think this is abnormal. It’s not. Try to distract the puppy with a game of fetch with their favorite toy, or get the puppy outside to run around. If you don’t have a yard, get a long line like this.
They come in 20 and 30 foot lengths and are great for letting your puppy run in an unfenced area. 
Because the puppy is developing an increased sense of social structure, the puppy may test his boundaries to determine his ranking in the family order, including the possibility of trying to assert himself over children. Dogs, especially young ones, see children as playmates. Kids are short, have high voices, are on the floor a lot and tend to be pretty physical when they play with the puppy. Basically, the child acts like a puppy, so the puppy is going to play with the child as it would another puppy – jumping, play biting, etc. Usually I see the puppy start to pick on the shortest or most mild-mannered child in the house. It can be scary for the child and they may run away, jump around, and/or squeal, which just gets the puppy more excited. This is a good time to put the puppy in the x-pen with some interactive toys. Children should NEVER be left alone with a puppy, or dog, for that matter. An adult should always be supervising.
At this age, especially closer to 24 weeks, hormones begin to kick in, making your puppy’s sexual behavior quite noticeable. Thus, this is a good time to start thinking about having the puppy spayed or neutered. Spay/neuter surgery not only reduces unwanted litters of puppies, but actually ensures a healthier life for your dog, including decreased risk of mammary and testicular cancer and less likelihood of the dog running away. Consult with your veterinarian about the appropriate time to spay/neuter your puppy.
