No, that is great!! Exercise is key in having a happy dog
. Keep on walking. As long as the temperature isn't too hot or cold, and he doesn't seem tired or thirsty, you should be fine. Walking isn't stressful on them like running is.
Glad to hear some one else out there exercises their Yorkie so much! Some people don't walk their Yorkies since they are small, but I highly disagree and I think all dogs should be walked no matter their size.