Two horses were injured during filming and later euthanized. The American Humane Association (A.H.A.) released a statement saying that both racehorses suffered severe fractures that were checked by veterinarians and deemed inoperable. The People for the Ethical Treatment of Animals (P.E.T.A.) criticized HBO over the injuries and euthanization of the horses. After the death of a third horse, HBO suspended any filming involving horses while investigations by the A.H.A. took place. It was determined that the third horse was not injured during filming. HBO decided to cancel the series rather than risk any further animal injuries.