just wondering, at what age does a male ASF stop/slow down on impregnating the females?

originally i got a 1.1 pair, who was a kid's pet that got wildly out of hand. when i received them there were 14 weanlings in a separate tub, and another set of pinks that had just been born. i grew up some of the babies, and now have 2 colonies of 1.4.

the second colony contains the original breeder pair, and i added 3 other females, as the other male i grew up got killed and eaten when the water bottle stopped working one day. when i added the other 3 females, there was a bit of squabling for the first night, a couple squeeks and a few "tumbleweeds" of various rats rolling around and fighting, but things settled right down after that.

the colony of 1.4 "freshies" is doing fantastic, keeping a very steady stream of rats coming.

the 2nd colony i just told you about FINALLY dropped about 18 pinks today (in a single litter, so i think it must be one of the newer rats that gave birth). but it's been awhile and they're not pumping out rats half as often as the other colony. so i'm just wondering if the male is getting old and tired of breeding. if so, can i grow up and add another male, and remove the original one, or will they kill him?

another thing i was wondering about, the original female gave birth awhile ago, however it seems all the rats died at about day 4 or so. but it didn't appear they had been killed, which is weird. there were just 6 dead, intact rats, and 2 that had been half eaten. i could see their skeletons sticking out, but they hadn't been completely consumed.

could they have died because the female is getting old therefor not producing very healthy young? i suspect her to be about 8 months old, if not older.

should i just scrap this colony and start a new one? or keep it going until the male dies? they all seem to be in good health but i'm just unsure when to retire the old breeders.

whoops sorry for the long-winded post!