pint sized puppy

Question
I recently got a 9 week old puppy who absolutely melted my wife and I's hearts.  However, we are concerned because, after taking her to the vet, we found out that she weighs only 5 lbs 11 ounces.  I know that this is not normal and her back and ribs show.  She is very energetic still and seems to be a happy puppy.  Our vet was new to us and commented about her size but said to just keep her eating.  We are feeding her Innova puppy food and we keep food in her dish so that she can eat when shes hungry, which is only about a cup and a half a day.  Is there anything else we can do to help fatten our new baby up?  Also, the parents were very healthy, the dad was 10 years old and was still in amazing condition.  Any help would be greatly appreciated.  thanks.

Answer
Some puppies are just smaller, though her weight at 9 weeks is very tiny!  If you're sure she's purebred (puppies in a litter can have different fathers), and about the age (some breeders will lie in order to send the puppies home earlier), and if the vet says everything else is fine, then it may be that she's just going to be a small Boxer.  

I'm not generally a fan of free-feeding (it wreaks havoc with housetraining and manners training, as well as the potential choking hazard) but I know it does work for others.  At her size, I'm thinking the dry kibble might be difficult for her to eat, so soaking it in some warm water or goat's milk for 10 minutes or so before feeding might encourage her to eat more. (I wouldn't leave soaked kibble sitting out, though, especially if you use goat's milk; if you want to still free-feed, then you could give her soaked kibble three or four times a day and leave the dry out.)  Innova is a fairly decent food; if they make a canned puppy food, you might try giving her that a few times a day, instead of the soaked kibble.  As she gets older you can add in healthy extras like ground beef, chicken, scrambled eggs, cottage cheese - in moderation as too much can upset the nutritional balances.  You can start adding them now but I would take it slowly as her digestive system is still 'learning' about new foods.

Good luck!