Only male golden retriever dogs have chest hair, female dogs do not. Generally, male dogs will lose their fetal hair at 4-8 months, and then grow new hair. Chest hair will grow around 7-8 months of age. As adults, they also shed their hair in spring and autumn every year. The chest hair of adult golden retrievers generally begins to develop after one and a half years old, and the best period for hair development is between 2 and 5 years old.