You mentioned your pups are Australian Shepherds. Are they breed standard?
I only ask because as a single breed standard, their natural genetics is to protect and herd.
But when you have two, untrained pups either spayed or neutered, that changes things a lot.
They will act "pack like" doing...
My heart is saddened for you and your chicken. You did the right thing as sad as it was to cull her.
I am so sorry you had to make the agonizing decision to do so but, you made the right decision.
RIP little one, you are no longer in pain nor fearful. :hit:hit:hit