HBO Many people heard that filming of the HBO series "Luck" was canceled when four horses died.

The Hollywood Reporter just published a stunning investigation suggesting this is just the tip of the iceberg of animal abuses occurring in the film world.

The American Humane Association (AHA) is the group that watches over animal welfare and awards films and TV shows the "no animals were harmed" moniker. They send representatives to watch over filming of movies and TV shows.

While the AHA once played a huge role in making Hollywood safer for animals, many recent incidents suggest that their work today in inadequate. Even those within the AHA who spoke to the Hollywood Reporter have lost hope in their role.

But the problem, according to the article, is that the AHA's flexible application of the "no animals were harmed" credit leaves plenty of animals harmed. Notably, the credit doesn't apply during hiatuses in filming, when the harm wasn't intentional, or if the harm happened when the cameras aren't recording.

Here are some allegations made in the investigative report: