Hello. I have a 3 year old male silky terrier and a 4 year old female Yorkie poo. Recently a brown lab puppy has moved in behind me. Not sure of its sex. My male dog is going crazy trying to bite and get to this lab. We even put lattice work over our existing fence to provide some security. My male will not let him alone the entire time the lab is out. My male will bark consistently at the dog, bite at the lattice work and run back and forth. He is normally submissive to my female and this is very out of character for him. Any suggestions/ideas???