Growth depends on the lines, the parents. At 8 weeks Zoey was a robust 16 pounds but Aimee was a petite 12 pounds but both gained 2 to 3 pounds a week. Your food amounts sound about right, ive never had a 6 week old so thats a guess, and you will probably increase that in a few weeks. At 8 weeks both of my labs were eating 1 cup 3 times a day and Zoey increased at 12 weeks to about 4 cups, Aimee was smaller and stayed at 3 cups