You've already received very good advice. I just wanted to add that I've been reading from the more experienced yorkie people that yorkies mature a lot slower than the other dog breeds. They're "full grown" by a year but emotionally/mentally they take a little longer than other breeds. I saw in a thread the description of what ages what and how a yorkie develops (this is before 12 weeks of age) but I can't find it at the moment. I'll search for it later. Anyway, it sounds like your pup came to you before it's 12 weeks of age which means it didn't learn any social skills from it's mother and litter mates. Some of the things they learn are potty manners, (not fully potty trained, but mother and breeder help give them a head start) bite inhibition (where they learn from mom and siblings that biting actually hurts and they learn how to use their mouths properly) and they also learn how to socialize with humans. Those could be reasons why your Yuuki is nipping at people's toes, and peeing and pooping everywhere. As for the name, it takes a little time. Kaji came home on his first birthday and he was Bear for that first year of his life. In his new home he wouldn't even respond to Bear. It took him a while to fully adjust and learn Kaji was his name. Now he response to Pooper, Munchkin, Pawpaw, Bebe, Kachis, Kachito, and any other cutesy name we can think of.
