I am getting rather concerned that there are a number of people who have purchased their puppy from a pet shop at a very young age, some even as young as 6 weeks of age.
Folks this is way too young for a puppy to be separated from its mother. It also means that the puppy was in the pet shop and all alone from an even younger age. This could mean a whole load of health and psychological problems for the pup...
And I hear that the pet shop people have told the new owners that these young puppies only need to be fed only twice a day. This is completely untrue. They need to be fed small meals up to 4 times a day or every 4-6 hours depending on the pup and the breed.
People, please do your homework before getting a puppy. And if you must get a pure breed puppy, do consider looking at the various rescue groups and organisations for your puppy. If not, go to a reputable breeder at the very least. A good breeder will not let you take the pup until it is about 10-12 weeks old. But never buy your pup from a pet shop because chances are that pup came from a puppy mill!
And what is more worrying is also what people are advising these new puppy owners. I am sorry but Cesar Milan's methods are outdated and detrimental to a dog's well being (I have attended his seminar in London a few years ago and had a VIP Q&A session with him - he knows nothing about dealing with problematic dogs. His shows are a huge success as a result of good videography and clever editing!)
A puppy that is so young and separated from its mother and it's litter mate, and has been in a harsh pet shop environment is most likely suffering from separation anxiety and stress. You need to deal with these issues in the right way, and not attempt the nonsensical pack leader mentality.
You need to make sure that your pup is comfortable and feels secure. Crate training is one of the best ways to do this contrary to the mind set of most people here who are anti crate training. You should also leave a hot water bottle to keep it warm at night and a clock wrapped in a towel to mimic the mother's heart beat.
I could go on and on about how to manage this, but the bottom line is, PLEASE DO YOUR HOMEWORK BEFORE BRINGING A PUPPY OR ANY DOG INTO YOUR HOME.
It is a lifetime commitment guys... and if you're not prepared to care for the pup for the next 10-15 years no matter what, please don't get one.