Can anyone tell me how long a Shitzu stays in heat and how long during that period is she capable of getting pregnant? Thanks anyone that can help.

A bitch is normally in season for 21 days. Unless you know when she ovulates, you won't know when she will be at her optimum mating time ie when she could get pregnant. Some bitches will ovulate early in their season & others later in their season. She could get pregnant at any time during her season.

Hope that helps.  :)

Dogs of any type are individuals and although the norm is around 21 days and ovulation takes place approx. between day 10 and 15 there are a lot who may be ready at day 6 and some will stand until well after the 20th day. So you need to make some sort of check, a resident stud and an experianced owner is about the best, but there are other ways, so speak to your vet about it. Or the bitches breeder who will know what is normal for that bitches lines and that will help give you some idea of when she may be ready, she may not of course follow what is the norm for her lines.