The gestation period for dogs is between 57 - 63 days approximately nine weeks. Why the variance because we commonly count the days from mating rather than from ovulation. Mainly due to the fact that we often don't know the specific timing of ovulation. As you can imagine this gestational period is a crucial time for your puppies development and any number of things can affect this. However all going as mother nature intended the gestational timeline would look something like this. 

Canine Gestation Development Timeline

1st WEEK

  • Day of first breeding.
  • Sperm migrate beyond cervix.
  • Sperm travel through oviducts. Sperm may survive for as long as 9 days.
  • Sperm reach the oviducts where mature eggs are located.
  • Fertilization of the egg (in the oviducts). and migration into the uterine horns.

2nd WEEK

  • Eggs develop into blastocysts.
  • Embryos enter uterus.

3rd WEEK

  • On day 19 blastocysts implant in the uterine wall, forming embryonic vesicles.
  • On day 22 embryos are visible.

4th WEEK

  • Eyes and spinal cords are developing, and the foetuses are beginning to grow facial features.
  • Organ formation begins - at this time the embryos are at the highest susceptibility for defects.
  • Embryos are approximately the size of a walnut, placed evenly in the uterine horns.
  •         Foetus can be felt in the uterine horns around day 28, and can also be seen by ultrasound.

5th WEEK

  • Toes, whisker buds and claws begin development and begin to look like actual puppies
  • Organ formation (organogenesis) ends.
  • The fetuses now look like a puppy dog, displaying head and trunk differentiation.
  • The foetuses develop their sex organs and gender can be determined.
  • Skin pigment begins to develop.
  • May be able to hear fetal heartbeat with stethoscope.

6th WEEK

  •         Puppies continue to grow and pigmentation develops.
  •         The eyes now have lids and remain sealed until approximately ten days after birth

7th WEEK

  • Bones begin to mineralize.
  • Puppies are easily felt through abdominal wall, although hard to count.
  •         Puppies are well-developed, and now begin growing in preparation for birth.
  •         You may be able to see/feel the puppies' movements in your bitch's abdomen

8th WEEK

  • Puppy movement easily detected.
  • Puppies have all their fur and are now crowded in the uterus.
  •         They become very active as they get into position for the coming birth. 

9th WEEK

  • Movement starts to decrease due to abdominal crowding.
  • The puppies are ready for birth.