Before breeding from a bitch, make sure she is in good condition. A thin dog is going to struggle to support the growing foetus' nutritional needs. An overweight dog may experience a difficult labour. A good quality adult maintenance food such as JB's Good Food will help maintain good health.
Normal gestation is 9 weeks, with the majority of the weight gain in the last 3 weeks, when the bitch will need up to 50% more food energy. Increase the quantity of food after week 6, changing over a period of 7-10 days to a more nutrient-rich Puppy Food so that volume of food doesn't get too large.
After giving birth a bitch will lose weight and nutritional needs increase by up to 2-3 times above normal adult requirements, depending on litter size, so that she can produce sufficient milk for the pups.
Continue feeding a nutrient-dense food such as our own JB's Puppy Food and rather than increasing volume, feed more frequently or free feed with unlimited access through the day.
By around 5 weeks, pups start taking an interest in their mother's food, and taking less milk. At this point the mother will need progressively less food until, at 8 weeks or so when the pups are weaned, she can be changed back onto the normal adult maintenance food whilst the pups are eating the Puppy Food.