Okay so, Seeker is 9.5 weeks, broken foot, going strong

No really, he was eating wet food and this am, i brought him down from our room put a 1/4 of his Nutro Natural in the bowl, and he ate. maybe a 1/4 of it, but he was there eating. then he pooped on his pad. So here is my question, how much food should a 1.6pd puppy be eating? should i still buy Nutrical and have it just in case, or should i be givingit to him regularly?thanks.