I'm sorry you lost a hen. I'm sorry you lost that hen violently. I'm sorry the neighbors lost their cat and that there will most likely be "hard feelings" over all this.
Was your hen a small hen? Was she weak for some reason? I don't think that any cat in my area could "take" one of my larger hens... maybe one of the bantams, but not if the rooster was near. My own cat only "eyes" and "drools over" the baby chicks, doesn't even think of "taking on" the full grown hens, or even the bantams (And, won't go after the babies with mama hen nearby). It seems odd to me that a cat could catch, hold and kill a hen? Do you know how it happened, or that it was the cat for sure? Are there other predators in your area?
If my cat goes to my neighbor's house and gets killed by their dog... that is my cat's problem and fault. Heartbreaking, but true.
I have put bells on my cat's collar, so that all the birds can hear her coming and have a better chance. She also comes in and stays in at night, and the chickens go into the coop for the night.
Best of luck.
