I wouldn't worry about your baby's ears not standing up. At 12 weeks a yorkie puppy is going through its teething phase, and that will last several weeks. For some reason, nature knows better and puts everything into the building of permanent teeth and the ears tend to get floppy for awhile. It most likely will pass and the ears will stand on their own. Just help out by keeping the top third shaved down so there won't be that extra weight on them. Good luck!
