My hens enjoy free-ranging and I have been lucky avoiding predators. My birds walk onto the patio, jump into deck chairs which is amusing, but the poop gets annoying. My hens usually return to their nesting boxes to lay. They may eat anything they can reach: flowers, tomatoes, ivy, etc.
I am sorry to hear someone's pets killed yours. Contact your local sheriff's office and inquire about your rights and how "pet on livestock violence" has been addressed in the past. Although it is not your fault, it is your best interest to secure your flock more robustly and protect your...