I just went yesterday and saw my mentors single pup. He is 5 1/2 weeks old now, he also weighed 1 lb. 2 oz. (we weighed him while I was there) He seemed like he was going to be pretty small, he had a nice round belly becuase I am sure he ate really great being the only pup in that litter. If the chart is accurate, which I have no idea if they are or not, it said he should be 4 or 4 1/2 lbs. Which is 'small' in my opinion. He's so cute I may buy him!
"What chart are you looking at? "
If you type in "yorkie growth chart" on google, it will give you many choices to see charts. Click on any one and they all seem to be the same. (no idea how accurate they are)