I would also separate the females from the males before they lay( Erm... In the mammal way) I have heard more bad story's than good when keeping the male in with the female, sometimes it works out good, and in your case, badly. I'd defiantly feed these off and get another group, your best luck to find breeder sizes is to go find a good mom and pop pet store that has mice( pecto or petsmart mice did not seem to want to breed for me...)or look at your local craigslist. This worked out great for me and now i have alot of pregnant moms, and the ones that had baby's, still have their babys... who need to be weaned soon...