Not sure which breed of Hamsters you are talking about. If they are Dwarf Hamsters then the Male will definately have mated the Mum on day of giving birth. Yikes
When the Mums babies reach 18 days to 3 wks old she may kill any babies left with her as she feels they might be a threat to the next litter. I have been breeding Dwarf Hamsters for quite a while so also know to get the Father out as Mummy will get exhausted having 3 litters in a row. Accidents always happen as we know & the deed is now done. If you have a housing problem, how about making a bin cage for Dad & another for the babies when they're old enough. Good luck with all.
