Dont understand your troubles they are by far the easiest rodents to breed !:confused:,if you had them a year & only have 20 I dont get that you should have had 100's!.feed off the whole group & start fresh.remeber 1.3 or 1.4 groups ONE MALE TO EACH GROUP!!!,CANT MIX MORE THAN ONE MALE THE WILL FIGHT & KILL BABIES!