
i have had a litter of 12 and 13, all puppies done just fine with no supplementation at all except puppy stim given to a very small boy twice a day for the first 2 weeks.
the important thing is to rotate puppies on the teats, i feed half of the litter then the other half to ensure everyone gets their fill, it is VERY tiring for those first few weeks to make sure they are constantly suckling as by the time the first lot of puppies have fed and fallen to sleep, you swap the other half and then its time to start again, no break so hope you have some help at hand, but the best for them is their mums milk.
Good luck with your litter :)