Hamster behavior/Breeding

Question
I have six Syrian hamsters-three males and three females. Recently, one of the females escaped for four days-she came back skinny but she ate a lot and is now almost back to normal. The problem is, the rest of the hamsters attack her every time they see her. Also, she is pregnant! When she escaped, she wasn't! I don't know how she got pregnant or what to do now.

Answer
hey,
i'm glad your hamster came back.
  If they are serian hamster they should not be together in cage or otherwise unless introduced for mating and even that its only a few hours. Serian hamsters are not sociable animals and need their own space. if she went missing for that long the hamsters won't recognise her anyway and its not a good idea to put her back in the cage at all becuase serian hamsters fight to the death.
 How do you know she is pregnant? the only way to tell if a hamster is pregnant is to put her with the male when shes supposed to be in heat. her belly will start to grow by 10 days, but sometimes even for an expert its hard to tell if she is or not, you can compare with pictures on my site
www.angelfire.com/jazz/hamsters
 hamsters are pregnant for 16 days, so its likely to be she got pregnant before she went missing, unless you have random male hamsters roaming your house ;-)
  If you still think she is pregnant, and her belly feels tight underneath she should have her own cage ready for babies, she needs to have tissue paper bedding rather than fluff becuase that won't get tangled in babies limbs.
  you mustn't touch the babies until they are 2 weeks old, and give them lots of extra food from 5 days, when they start roaming the cage move the water bottle for them to reach it.
  let me know if you have any other questions!
~suz