Have you separated the babies into girls and boys?
What type of diet are you feeding the hamster?
Are any of the other babies having problems?
I have not separated the babies yet because I did not think they were old enough; their eyes aren't open yet. The food is sold by weight so I am not sure what brand it is but it consists of oats, seeds, dried fruits and vegetables and assorted dry food pieces. I also give the older hamsters boiled eggs and noodles so the babies do have access to them. The other babies appear to be healthy.
The Pups eyes should be open by 14 days of age and they can breed as early as 4 weeks of age. They should be removed from mom between 21-28 days. If they are close to 5 weeks of age, You really need to get the hamsters into a Rodent or exotic Vet to be checked out, because something is wrong with their developement. you can read more about that here: http://www.hamsterific.com/RaisingPups.cfm This may be a result of the inbreeding between the sister and brother as parents. As far as the little one who is having the problem with the stools, this also may be a result of the inbreeding. The grey stools are not normal and this may be a problem with the digetive system. I am going to give you a link for Vets that can treat hamsters: http://www.aemv.org/ or these are Rat Vets that treat all rodents: please put the word member in each blank: http://www.rmca.org/Resources/vets.htm/
I would have the Pups seen asa soon as possible because it seems there is a problem with thier developement. Joan