Is this the first time your females are giving birth? I personally noticed that my asfs look greasy when they start to get old and when their diet was too fatty like you mentioned. I used to throw in all kinds of fruits and veggies and they looked little greasy so i cut back to just lettuce and the lab block with the occasional snack and they look much better. Once they get past a year old though i noticed they can start to greasy or lose patches of hair. (old age i'm assuming). Sorry i'm can't help more but that's my thoughts for whatever they are worth. Hope it helps