The only reason I see someone would have a reason to breed would be if the parents are in perfect health and if they have something to give.

Gr.. I can't really get out what I'm trying to say.. It's like this:

The only reason you should breed Border Collies if it's parents proove themselves to be amazing working dogs, because that is what they are bred to do.

Personally, and no offense meaned, I would spay your Yorkie. Of course, everyone wants a puppy. All puppies are adorable. There is no such thing as an ugly puppy. But when it's all grown up, not housetrained, no basic obedience is down, no one wants it.

You have no real 100% guarantee when you sell a puppy that the buyers are going to live up to their word one year or more down the line.

Sad, isn't it?