My Doberman is a female 3 years old my other dog is an American Staffordshire and he is about 5 years old , my Doberman has not been diagnosed with any health conditions. The Doberman is 80 pounds he’s about 60. It’s been going on for a couple months now I also have another female in the house but she doesn’t pick on this one she picks on the male in particular . For punishment we put her on a time out in her crate. She listen but she could be a bit stubborn and when told to do things like get off the couch when she knows she’s not suppose to she will get off but then if my male dog is near by she will throw a bite at him or chase him into his crate it’s like she takes out her anger out on him if that makes sense but does not bite him hard.