The UK DVD release has been re-edited to remove all instances of horses being trip-wired. According to the British Board of Film Classification, such a tactic contravenes the 1937 Cinematograph Act which forbids the ill-treatment of any animal in the making of a film (although some stuntmen claim that the method can be performed without harming any horses).
Robert Aldrich privately admitted that he wasn't entirely satisfied with the way the film turned out.
Filmed for $1.2 million in only 7 weeks, a good 3 or 4 weeks less than most of Robert Aldrich's movies.
Although technically not credited as such, Burt Lancaster was virtually a producer on the film, helping bring it to screen, taking points instead of an upfront salary and having a say in the editing stages.