Just like human babies, puppies go through a lot of different stages and phases on their way to adulthood. Every puppy is unique- a furry little bundle of wants/needs/instincts and genes. As puppies grow, you learn more about their personality and you will find it easier to cater to their needs. If you want to see how quickly a puppy grows in the first 45 days, here is a collection of clips from YouTube. This amazing video is from newborn puppy to 14 days old puppy. I am sure you will like this video and get to know lots of information about puppy development