My syrian hamster gave birth yesterday on 20/4/2010. All the babies were kept in the small house

i can't see how many llitter are there. Today i saw some came out when mother go out to get the food, zone of them stuck under the house. i didn't know either the mother. Suddenly i saw the house is not in the correct position and i tried to turn it and saw one had died. So sad. How to deal with it and what should i do to prevent it happen again. When can i clean her cage

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