About two hundred to three hundred horses were used in the trilogy. Because most of the scenes involving horses are intense battle scenes, where the horses could likely be harmed, a horse and rider were fitted with the same type of suit that Andy Serkis wore for his role, and were filmed in the studio doing typical "battle" things, like galloping and rearing up, so the footage could be inserted digitally into the battle scenes. In that way, no horses were hurt.
The battle at Helm's Deep was edited down from twenty hours of footage, shot over a four month period with the rain machine battering down on the cast.
Viggo Mortensen was so impressed with the horse his character rode that he purchased him from the owners. The horse was shipped back to New Zealand for the additional shots that were filmed in 2002.
Viggo Mortensen broke two toes while kicking the steel helmet by the orc pyre, and that take is the one that appears in the final cut. Director Sir Peter Jackson said that he was really impressed with the shout of pain Aragorn cried out for the fate of the two Hobbits, realizing only later that it was real pain for his toes. He was also impressed by the fact that Mortensen continued acting, even while so seriously injured. Mortensen later remarked that the only reason it was even mentioned, on the DVD release, was because he was an actor, and that the stunt crew were injured far worse and pushed through it.
They couldn't recruit enough men in the six foot height area to play Uruk-hai, so men from five foot high were cast as well. They were affectionately nicknamed the Uruk-Low.
Alan Lee: The concept designer can be seen as the Rohan collecting weapons at Helm's Deep (to the left when Aragorn yells "Then I shall die as one of them!").
Barrie M. Osborne: The executive producer appears as a Rohirrim soldier throwing a rock down on the Uruk-Hai attacking the gate at Helm's Deep.
Dan Hennah: The art director is getting suited up in the armory at Helm's Deep. Look over Aragorn's right shoulder after Legolas says "They're frightened, I can see it in their eyes."
Peter Jackson: [children] Jackson's children Billy Jackson and Katherine Jackson appear as "cute Rohan refugee children."
