On the set of the HBO series The Gilded Age, history has repeated itself in more ways than one: Multiple whistleblowers told PETA that a horse died, which may have prevented the network from sweeping this incident under the rug.

After receiving the complaints, PETA contacted HBO executives and producers for more information about the alleged death of the horse—who, according to one whistleblower, suffered from head trauma and was 23 years old with preexisting health conditions. The complaints revealed that the horse was seen “severely frothing” at the mouth. HBO has confirmed reports of the horse’s death in the press, stating that the horse “collapsed and died, likely of natural causes,” which leaves more questions than answers.

Apparently, HBO’s standards for animals used in productions are as backward as its period dramas. Horses have died on an HBO set before: A decade ago, the network tried—and failed—to sweep the deaths of three horses on the set of the series Luck under the rug.

When HBO’s execs refused to come clean about the deaths, we learned from whistleblowers that one of the horses had been given a cocktail of potent drugs and that another was 8 years old and arthritic. After PETA catapulted news of the deaths of the horses into the public eye and pressed law-enforcement officials to launch an investigation, the network canceled the series.

Despite our win for horses back then, it seems that HBO hasn’t yet learned its lesson. PETA penned a letter to let the network know that this pattern cannot continue. We’re demanding that HBO launch an investigation into the death of the horse and stop using horses in its productions.

Help Horses Exploited by Hollywood

PETA has revealed that horses have been injured and killed during several Hollywood productions, including Flicka, American Outlaws, Simpatico, The Hobbit: An Unexpected Journey, and War Horse. On film and TV sets, horses are often pushed past their limits, forced to perform dangerous stunts, and terrified by their highly unnatural surroundings.

Networks like HBO have the money and resources to use humane and realistic computer-generated imagery as well as other alternatives instead of live horses, so there’s simply no excuse for exploiting these sensitive animals, let alone allowing them to be injured or killed.

You can do your part for horses by taking action below: