We have a new Jack Russell female (now 7 months) who we have introduced to our 11 year old (both Jack Russell, both female) who were getting along fine the last 5 months. We introduced a new male kitten two weeks ago and have been very proactive in the introductions which have been working really well until tonight. I think we may have done something wrong separating the introductions (thoughts of 2 Jack Russells against a kitten). The younger who is probably vying for dominance has been vicious over a joint meeting of the kitten to the point of attacking the elder female dog and drawing blood and will not back off even after they have been separated. We have had to isolate their sleeping arrangements tonight (as they always sleep together), want to nip this in the bud asap before it esculates. Any help appreciated.