Fighting?

Question
Hello,
my first ferret i got in April at around 10 weeks of age. In the summer me and my sister were cleaning out the cages and my ferret was running loose and when me and my sister went outside to rinse the cages down my sisters chinchilla managed to push its cage over the edge and got loose too. they both ran under the couch and my ferret killed the chinchilla. it was a pretty hard thing to find and my sister was really upset. after that my sister choose to get a ferret as well since she liked mine. she got her ferret in aug. we have placed there cages beside each other since then and have only had them together when we are holding on to both of them. they are around the same size now but I'm scared to let them loose together after what happened before. when we are holding them my ferret will attempt to bite the other one. Is it safe for me to allow the loose ever... or has my ferret got the taste for blood? how should we go about a safe way of moving them together.

Answer
A chinchilla is a prey item and another ferrets isn't.  the introductions may be loud and look bad to you, but neck biting is very normal.  The best thing to do is allow them to play together as soon as you get them, but since you waited, you need to place them both on the ground and let them meet each other without you "helping".  They should be fine and only pull them apart if there is blood.