My dog is a killing machine. Why?

I used to have two pomeranians. Zeneth and Zorro. They were really attached to each other. They had puppies together and the male, Zorro, guarded Zeneth and the pups and even brought her food. Zorro was older than Zeneth, and when he got too old to defend his food from other dogs Zeneth helped him. They got depressed if they were apart. Last winter Zorro passed on in his sleep and Zeneth led me too him. When I buried him, she saw me and would not let me touch her for a week. She still goes out to his grave and visits him. (Strange, I know.) After he died she started killing. Rabbits, baby pigs, chickens, my pet duck, a baby goat, my dog's puppies, a kitten, squirrels, my neighbor's dachsund, goldfish,pet birds, frogs, a baby stork,(dont ask) an opossom, turtles, and anything else she can catch. She isn't even allowed in the room with my chihuahua. Her eyes turn solid black and she starts breathing hard and you just know she's about to kill. Is this because Zorro died? She still looks for him when we say his name.