we raise alot of Asf's and know what you are talking about. our experiance is that if the group is already a breeding group and you introduce a new member they will fight like h*ll. we, like mike seperate our young by sex into grower bins. ( I'm pretty sure I read Mike does this). I have reaised them in there and decided to make new colonies out of there and never had aggresion troubles. so what all that rambling means for us we make new colonies out of weaned rats or out of rats that havent been with the opposite sex since they were weined.

I have added new females to the old colonies ( and males) and have had alot of fighting but never a blood bath. they get there pecking order down and thats that, maybe a fight here and there when treats are introduced, but only lasts for a second or two.

hope this helps.

Eric