Animals in the wild don’t age gracefully and go to hospice where they die in peace surrounded by family and morphine.
There are 4 main ways an animal dies “naturally” in the wild:
1) slow starvation due to lack of food/winter
2) slow starvation due to being injured or a health issue
3) slow, painful starvation due to being maimed by a predator
4) being violently eaten alive by a predator
Any of the “killed by a human” options are far more humane.