All puppy coats are eventually replaced by adult fur. No matter how soft and fuzzy, that puppy coat is temporary and must turn into adult fur as the puppy grows. The timing of this varies, but it usually happens between 3 and 6 months of age. This depends on the breed, puppy’s health, and climate. Whenever it happens, the process looks similar: puppy’s coat becomes shaggy and may fall out before adult fur manages to replace it. This is completely normal and should not be taken as a sign of a health problem.