My family has two Australian Cattle dogs. One (light color) they had before getting the other one (darker color) to keep her company. They essentially grew up together because the oldest was only 1 year old when they got the second.

They get along but then all of sudden a vicious fight will break out. These fights have gotten progressively worse and now my mom has chunks of her skin gone. She stupidly separates fights with her hand. It seems the fights start over possessions whether it be toys or their undying love for my dad.

These fights are always started by the younger dog, and the older one will fight back but never as vicious, she’s becoming scared of the younger one. And my dad is using a shock collar on the younger one now! Which is super upsetting and I’m fully aware that it makes the situation worse by creating anxiety and pain. Have any of you experienced a situation like this and what do you recommend? A trainer? Rehoming the younger dog? She’s VERY attached to my dad but I believe she’ll learn to love another household if it comes down to rehoming.

Thanks for your help in advance.