It depends on a lot of facts that are not present here. Why was the horse euthanized? Did you actually tell the vet you did not want the horse euthanized? If you did, what was the vet's response? Why was a necropsy done? Was there suspicion of an infectious disease? Was the Department of Ag or an animal welfare group involved? Are you a boarder and does your boarding agreement allow the barn manager to authorize euthanasia if you can't be reached and the vet advises it? Are you a minor and did your parents authorize the euthanasia?
If we do not have a signed fee agreement I am not your attorney and this is not legal advice.
Without knowing the reason for this, such as whether or not the horse was injured, it would be impossible to tell you.
Philadelphia Personal Injury Lawyer. www.InjuryLawyerPhiladelphia.com