
I only had two survivors in my litter and I did find the milk started to dry up too soon (the mum was also unwell which might have contributed)...
I kept putting the pups on regularly to different teats to stimulate the milk production, empty them all(to avoid infection) and also to make sure I knew the smaller one got regular feeds and the weight kept going up.
I managed to keep the milk flowing long enough but did start weaning reasonably early as I had a feeling the milk she had will not be sustaining them for very long.
Good luck with your little ones!