I'm sorry to hear this happened to you - in relation to your rights regarding your dog being declared a dangerous dog - I'm sorry to say but unless you fight this in court you have no rights. You can google "dangerous dogs rights" something along those lines and you can see lots of support on line but unless you take it to court to fight it, you can't get out of your dog being declared a dangerous dog.

I really feel for you, our two dogs escaped 2 years ago and allegedly killed a goat. Our option was to fight to have them declared dangereous dogs or to have them put down. Due to their breed (not pit bulls or anything like that but just active dogs) and other situations we made the heartbreaking decision to put them down.

I am sorry your in this situation and I hope that you are able to keep your dog under the dangerous dog classification. I would do some googling re the chickens and the fence arrangements but I think you'll find that because it is seen as your responsiblity to keep the dog contained, then it won't matter what happened on the other side of the fence.

Hugs and good luck, sorry I couldn't be more helpful.