Wobbly puppy

[1desertbrat]

Hello fellow canine lovers!
I have a 3 week old Wirehaired Pointing Griffon pup that has me stumped. She was a bit small at birth, but not the smallest pup, however her rate of gain is 63% less than that of her siblings. I ensure she gets "one-on-one" time with mom several times a day and she has a hearty appetite, but never seems to get full. Although I am concerned about the weight, I am more concerned because her equilibrium seems to be off. She acts drunk when she walks and her head bobbles. She also has an umbilical hurnia, but I don't think it's related to the problem.
I took her to the vet a few days ago and he ran some blood tests thinking she may have a liver shunt, but the tests were "inconclusive". He said she was a bit anemic but other than that, her blood was fine.
Apparently there are other blood tests specific for liver shunts, but as fasting for several hours is required, we will wait until she is a few weeks older.
Do any of you have any other suggestions as to what it could be?
Any help in resolving this would be greatly appreciated!
Desertbrat

[marko]

Bobbling head....No ear scratching right - which might indicate mites? Vet looked in the ears? (Sorry but had to ask, just in case)