The average length of the gestation period for dogs is between 60 to 64 days, or roughly 9 weeks. However, as with humans, the length of the gestation period varies slightly depending on the female. The duration also varies between breeds.
When a female dog enters the early stages of her pregnancy, she is often much less interested in food and less willing to engage in physical activity. She may also exhibit behavioral abnormalities, such as increased displays of affection or an uncharacteristic desire for solitude. This is because she is undergoing hormonal changes similar to those experienced by a pregnant woman. After the initial weeks of gestation, her appetite should return to normal. There is noticeable weight gain and her abdomen becomes very firm after the fifth week. If she is carrying a very small litter, however, she may not be noticeably larger until her delivery date is almost upon her.
A female dog's nutritional requirements almost double as she nears the end of her pregnancy, and she should be fed a series of light meals throughout the day as opposed to large meals twice a day. She should have unlimited access to fresh water, as she also drinks more than usual.