Golden Retriever Coat Stages. Golden Retriever puppies are born with fluffy, fuzzy hair coats. This fur is very soft and fine, and it helps to keep puppies warm due to its insulating properties. Golden puppies begin to grow adult hairs around three to four months of age, starting at the tail and then gradually moving up the body. These slightly coarser outer hairs are called guard hairs, and they push the puppy fur aside until the puppy fur forms an undercoat, which thickens over time.