I have a one year old 2 and a half pound yorkie and he's perfectly HEALTHY with no medical problems. The trick is that because he's so small he will have boundaries that my other dog doesn't have. IE: no stairs, no jumping up or down couches and beds, on walks maybe he'll be carried half the way while my other journey's on, etc... He can't just run around and have as much freedom as he'd want...he is very small and needs to have a mommy as tho he were a baby all the time. My other dog is 16 pounds and she's able to do all the things he'd like to but with training my tiny one still has the expectation of showing me with a "sit" near a chair or couch...that he'd like go up, or he jumps up on my leg when he'd like to be on my lap or in my arms. That kind of jumping is fine as he's healthy with no joint issues because I don't let him jump up on anything...and he'll never be allowed. We'll be building a ramp for our deck this summer so he can go up and down to get to the grass. Currently the snow has built up so much on the stairs that it has created a natural ramp with the build of snow and ice. It's easy to care for a tiny yorkie as long as you remember that they can't actually have the freedom that other small dogs have. My sis has a 6 pound yorkie and she's allowed to go up and down a carpeted staircase, but then again she's not allowed to jump up or down on couches... You have to consider your individual dog and be strict about it to protect them from themselves...
