Problems with new dog

[klleslie]

We have a 7 yr old male Min Pin, who typically has agression issues. My mother passed away in January and we have added her 22 mo old female Yorkie to our household. They have never loved each other, but the Min Pin accepted her being around from beginning. He lets her take his food which is a big deal---we have separate eating spaces now to avoid that. We had what I was calling an altercation once each day for the first few weeks, then about 4 days where everything was great. For about 5 days now, the Yorkie is openly agressive with Min Pin...she follows him, baits him and bites at him. Then the barking starts and I intervene and remove her to kennel and he gets taken upstairs (she cannot follow) for a 15-20 min timeout. Then I introduce back together very nonchalantly and they are good for a time and she starts again. I know she is female and asserting herself as dominant in home, but I cannot let her bea t up on Min Pin and I am forever keeping them separate when I leave the home. I separate them, admonish her and put in kennel. He gets reprimanded while altercation is ensuing as he listens to me better. I can make him quiet and settle---sometimes, otherwise he is biting at my pantlegs to get at her. I made them settle down today with a snap to end of her nose and a command to him and things were quiet and she starts growling and off we go. They are both in timeout and I am worn out. I don't like using my hands on them, she often responds to rolled newspaper that you hit against your hand, but not in these situations.

Any advice?