I know this is an old post but am curious because Manny's weight hasn't changed in a month. I buy his flee/tick pill monthly because he was close to the weight for a higher dosage so he's been weighed every month. Last month he weighed 9lbs, 4 ozs. When he was weighed again today he's still 9lbs, 4 ozs. and is 27 weeks old today. Do they start slowing down on weight gain this young or can I expect a spurt in his weight? Over the last two weeks I've seen a noticeable increase in his height but he seems to have really slimmed down.
So he stopped gaining weight at 6 months old? I would say that is not the norm. My guys all gained steadily for at least a year. Then they filled out. Bella is the smallest at 7 lbs, Fred is 15-15.5 and Scudder 16-16.5 lbs. Fred and Bella are on the very lean side. Scudder is bigger boned but I can still easily feel his ribs and backbone.
Keep an eye on his weight and the amount you are feeding, Keep it consistent. I would only be concerned if he started losing weight. Also, check with the breeder to see if her pups stop growing early. Find out what how his siblings are growing.