I just adopted a male black lab who is about a year old. I dont know anything about his past. He is a very sweet dog, and is really gentle natured. But recently he just started becoming really aggressive whenever i pull on his collar (leading him without a leash).
Please help this is getting pretty bad. Its almost where i cant control him with a leash.
Tonight when i was leading him back to his crate he almost bit me!

PLEASE HELP!

Small Dog Collars