QuestionDoes the female Yorkie have to be bred to a Yorkie that is smaller than
her and not the same size.?
AnswerHi Jessica
It's important to know the bloodlines on either side for at least 3 (but 6 is better) generations. There can be larger (or smaller) dogs in the pedigree and throw-backs are always possible.
The female in most breeds are smaller than than the males regardless. Smaller or the same size is a good start. But again, find out the lines to see if there are bigger sizes back there.
Good luck