Do wild animals being killed by other animals feel pain?
Undoubtedly they feel some pain, but your question is a good one, because they typically don't show any pain on their face even as they die a horrible death.
Two points I'd like to make:
- Most animals do not have expressive facial features because for most species it's advantageous for an individual to hide how it's feeling. For example, if a gazelle had a tortured look on her face from a stomach ache, the lion would know she's vulnerable and that gazelle would be lunch. So dramatic facial expressions are often not adaptive except in primates.
- Many people who have been in horrible accidents admit that to a LARGE degree they weren't feeling the pain right away. This is because when a traumatic event happens, the flight or fight hormones (endorphins and adrenalin) go surging through our nervous system, and for a few minutes the person is sorta numb. If you've ever seen a zebra get attacked by a lion, but then escape, you can see how the flight or fight hormones must be blocking the pain, or the zebra would just collapse immediately after being severely mauled.
Hope this helps.
Edited to remove incorrect auto-correct.