I have 5 children but this problem only applies to one of my children.
When we first got our JRT he would constantly hump my DS(7) DS is the quietest child of all my children and the less interested in the dog. I had the dog castrated as soon as I could and the humping stopped. I thought as it was only one child that the dog was displaying dominant behaviour but as it stopped was not worried. I have 2 toddlers also but the dog never acted the same with them or my older children.
That was 18 months ago and Dog is now 2. Just recently he has been lunging and snapping at the same child. Everytime child walks into the room he runs at him, barks and snaps at his heels, if DS sits on sofa, the dog will lung and snap at him. He does not growl it is a lunge and snap.
Nothing has happened to cause this. I never leave any of them unattended with the dog (he follows me everywhere) and DS is the only one who does not play with the dog so he has not hurt him during play.
It seems to be dominant behaviour over my son and only him but I have no idea how to correct it.