While I can't give you an exact answer, I know with my Shepherd I had to be careful with exercising him as a puppy.
As far as a lightweight yorkie, I would think that if you did some ratio (weight/bones,etc) the ratio would be the same whether you had a shepherd, a collie, or a yorkie.
But unless you are out making them run miles and not letting them sleep, I think they will choose when they have had enough and everything will be fine. |