I also think rehoming is the thing to do in this situation. You seem beyond stressed out and extremely frustrated and it hasn't even been that long since you've had the puppy.
You keep talking about how the dog is so old and "bad". If you already view him as a bad dog, that IS what he will be, I'm sorry but that's how I really feel. 5 months is hardly old, and still completely trainable. Maybe you just aren't ready for another dog -- because you could have ended up with a yorkie puppy who does the same things as the one you have now.
The nuetering will help with the marking and possible level out their hormones towards each other -- but they still need major training. If you do plan to keep this yorkie you need to call a certified behavoirist to get help with the aggression. Also, are you sure it's agression when the yorkie bites or is it mouthing? Mine bit as they were playing up until 6-7 months old, and I had to train them that biting = no. |