"Animal cruelty has been a fact of life on productions since the inception of Hollywood. (Nearly 100 horses died during the shooting of 1959’s Ben-Hur alone.) Action-adventure films and Westerns were known to treat animals harshly in their attempts to attain verisimilitude long before the advent of CGI. As early as 1939, after a horse was forced onto a slippery platform, tilted to ensure it would plummet 70 feet off a cliff to its death, during the shooting of Jesse James, the Hays Office, typically busy with other forms of morality policing, invited the AHA (not to be confused with the Humane Society of the United States) to be present on sets."
—That is the CHEERIEST part of the article "No Animals Were Harmed," so keep that in mind before you decide whether or not you want to click through.