Abandoned!
Public (street) Rescue years ago of a German Short Hair that was birdy and impeccably trained to hunt and obedient. I had no kennel/yard so left her in the apartment to go to class. Returned to a DESTROYED home. Couch cushions (all of them) shredded, drapes down and shredded, twin bead mattress shredded and defiled, you get the idea. All accomplished silently, according to the neighbors on each side and upstairs.
As long as she was accompanied the picture of a dream dog and upland bird buddy—
A part of the education I didn’t pay tuition for in college.
No Separation allowed.
Worst case but a consideration....