I started out trying to feed in seperate cages but soon learned that my bp would not eat if I picked her up first. It took her a good 3wks to start eating in her viv but she does great now. The thing I learned is a feeder cage doesn't have the temp/hum control a viv does unless you create a really good one so I can imagine it's a bit of a shock to their systems to be moved then expected to eat. I feed in the viv using long tongs and f/t mice (that's all she will eat). Have not had a problem with aggression at all.