Yorkies are one of the smaller dog breeds that are prized for their big personalities. When breeding Yorkies, also known as Yorkshire Terriers, it is important that you choose a male and female that are as close to the standard breed to deter any kind of genetic defects. Breeding Yorkies that have health problems will introduce defects and problems to the breed as a whole.
Do not breed a Yorkie until it is 18 months old. A dog that is younger than that has not fully matured and is prone to complications during the pregnancy. This time frame will also allow any kind of behavioral or genetic defects to show.
Visit a veterinarian. Have the Yorkie's health checked to make sure that the dog is in optimal condition for pregnancy. Do not breed a dog that has health problems because they can potentially pass on any defects to the litter.
Wait until the female is in heat. Heat occurs twice a year, in 21 day increments. It is best to introduce the female to the male during the middle of the heat cycle, when the female will be more susceptible to the male's advances. When she is entering heat, the vulva will increase in size and periodically have a discharge. The female's personality and temperament may change also.
Allow the female and the male to meet once she is fertile. Allow the female to mate with the male many times to ensure pregnancy.