This matter of yours is very simple, not as complicated as you think. First of all, you should have evidence to prove that the rabbit's death is indeed related to feed. You can prove it through the Consumers Association or a legally recognized inspection agency. Then negotiate with the manufacturer. If the manufacturer fails to solve the problem or deliberately delays, you can do further work through the news media and the Bureau of Quality and Technical Supervision. In short, there must be evidence and procedures.