I feel very bad for you and the loss of your chickens
I'm not sure where you live but I have 24 sweetheart pullets and hens love them all but I would be willing to give you a few if your within driving distance
Several states have leash laws and if the dogs get loose or left run loose the owner is responsible for any damage they cause.
Also Dogs are usually covered under the home owners insurance.
Example- My wife hit a dog with our car and damaged our car pretty good, we found out who the dog belonged to and filed a claim with the police and their home owners insurance company and won!! The officer is the one that told us about the law.
Granted the state I live in has a leash law and it is illegal for dog owners to let their dogs run loose thus the reason the dog owner was responsible for the damage to our property!!
In your case, 1st I would find out the leash laws in your state if there is one then file a police report then file a claim with their home owners insurance company.
Also many states have laws that state
If a dog is running loose and not on its owners property and a being a nuisance?? it can be shot on site.
I own 2 German Shepard's and love them dearly and consider them part of my Family BUT if I let my dogs run loose then something happens I am responsible for their actions and should pay for it because I knew that before I got them. If they would get killed because I let them run loose again It is my fault for letting them run loose on other peoples property and causeing pain and loss to others and I should Pay for it.