There are some Vets and Chiropractors that are offering animal chiropractic who are not certified. Please be aware of their education concerning animal chiropractic. It is a specialty and not part of chiropractic school. An untrained doctor can hurt your animal, you and or themselves and thus the law suite would ensue.
Ask what type of education they have concerning animal chiropractic and check one of these two websites to see if they are certified:
http://www.animalchiropractic.org/
http://ivca.de/