Any advice we have a 2 Year old 12 inc 13 lb entire little black fell terrier she lives outside very affectionate with people and our other larger male dog ,Got her 4 months ago with the plans to do a bit of ratting and mayby a bit of bushing for rabbits but due to my ill health she is not working, She's a great little dog in many ways the only problem is that she wants to kill anything smaller than herself small dogs, chickens baby birds any advice in way to calm her down or do you think she's to old to change.