With my regular rats the males are only in with the females for breeding purposes. As soon as the females show indications of being pregnant, the male goes back to the bachelor pad. The females rest after weaning their litter based on the size of the litter they raised.

With the ASF's the male stays in with his two females all the time. I've been told that with these rats, removal of the male from the established colony can result in problems trying to reintroduce him. Because the two females share nursing duties on all the young no matter who birthed them, it seems to be working out that no female is overly stressed. The father is very involved in the parenting and does his turn with managing the nest, keeping the young corralled and doing the regular face and butt washing duties while the females go off to nap and feed.