I have been a member on here for a while but usually i just read all the helpful advice, i've never posted on here.
I have an English Mastiff, he's just over a year old.
Bit of background info: he's a family dog, although he sleeps outside (his preference) He has full run of the yard (he's not contained in a run or anything) and goes for several walks each day.
He has been sterilised. He attended puppy school and is generally obedient.
He has however started showing signs of aggression. I can't say when i first noticed it, maybe it was always there and now its just worse. I'm not sure.
He barks aggressively when people come to the house, or walk past the front of the house at night, if someone comes into his yard, even if they are with a family member he will lunge and bark at them. He lunges at joggers and bikes, and is startled by sudden movement and young children running. He snapped at a young child once through a glass door.
He also blocks the doorway (however that could just be he can't be bothered getting up!!).
I have racked my brain and just can't seem to find a cause, he's been checked by the Vet for a medical reason. he's never been struck or physically punished. He seems fine with all the family (i have 3 young children and he will happily play with them ) and he's not food aggressive. He also seems to like other dogs
.
He doesn't usually display any of the behaviours (except the barking at people who come to the house) when my husband takes him out, its only when he's with me. Now I can't let him off the leash in case he attacks someone.
What could be causing this? and what do I need to do to stop it. Can i stop it? Where can I go for help before it gets any worse. I live in WA.
(He is NEVER left alone with our children, for his protection as much as theirs.)