AGBEH ( Aggressive Behaviors in Dogs group,) experienced dog trainers (more than 260 from around the world) discuss with pet dog owners how to modify the behavior of dogs which sometimes exhibit aggressive behaviors toward dogs and/or toward people using only positve methods.
I have been a a participating trainer in this group for 6 years. There are roughly 3,000 dog owners and 200 trainers. Highly recommended! Be warned. Follow the rules!!! Be sure to read the file section!
