Subject to the silliest of internet theories
There are a lot of movie theories but the silliest of all is this nonsense that is all over the internet claiming that the Chief killed the unresponsive McMurphy because he thought McMurphy was ignoring him.
These idiots claim the Chief did not notice the scars on McMurphy's head and simply thought the unresponsive McMurphy was ignoring him - so the Chief kills him in a fit of rage. Ridiculous.
The Chief killed McMurphy as an act of kindness. Chief was releasing McMurphy - a once spirited man now reduced to a vegetable thanks to the control freak, Nurse Wretched.
This classic movie still holds up after all these years and is a compelling story of blossoming friendships in a lunatic asylum. Nicholson shines in his best performance and is ably supported by Christopher Lloyd, Brad Dourif and Danny DeVito.