hello, need help with my 5 month old Border Collie puppy, he,s started herding and been very vocal.

Took him to a behaviour therapist last week which cost quite a lot of money, she told me that he was a bad dog and put a muzzle on him the full session, when he came home, he was a changed dog.

She told me to train and walk him alone, I have tried this, but i don't have a happy house now.

My gorgeous new friend has become aggressive towards his new friend and big brother ( my older dog ) every time they are separated.

When we do take them out together, people have told us what fantastic dogs they are and how well behaved.

The aggression is only at home and I feel that he is far to attached to me.

He is also teething at the moment and his mouth is quite sore and his gums are bleeding as his new teeth come through, could this be part of the problem.

Where do i go from here as they are both my best friends, any help would be most grateful.

Zack