menstrual periods for shitzus

Question
how long does a female shitzu have its menstrual period?

Answer
All dogs are individuals like we are, the usual is about 3 weeks.  They usually start with a bloody discharge which lightens some time during the second week.  It may then go back to a bloody discharge or remain light in color, but they are still in heat.  The thirteenth day is the fertile time in 90% of female dogs.    There are cases  of females being fertile as early as 4 days and as late as 25 days.  So keep her confined during the whole time to prevent any unwanted matings.
Nancy