You definitely have to separate them. I haven't heard any success stories of males and females not being separated for babies. Females can stay together with babies, but even then you have some fights and loose babies.

You won't know that she pregnant till the week before she gives birth. I wouldn't breed any till they are around four months, that puts them at about medium size I believe.

Also I wouldn't be feeling for babies. You shouldn't even hold them if they are pregnant.