This part mainly deals with the fishing trip, where the patients learn to fend for themselves in the outside world. Part III begins with showing McMurphy’s success after the broken glass incident and he has his own way for awhile. When he is refused an accompanied pass, he smashes the new glass. The glass is replaced a second time but Scanlon breaks it again with the basketball.
The Chief starts talking to McMurphy after fifteen years of silence, and his fog disappears. The Chief talks a lot, he explains to McMurphy about his father and mother and how their land was taken away from them in order to build a dam. He says that his mother was a very big woman, but his perception is clouded by his paranoia about size and power. She was big to him, even though she was only five feet nine, because she seemed so powerful. He tells McMurphy that his father was also big, but his mother and the Combine belittled him into smallness. As a result, the father drifted deeper and deeper into alcoholism. The Chief blames everything bad on the repressive society that was capable of seizing his family’s land and destroying his father. When he was a boy, he says people treated him as if he were invisible. The Chief learned to listen and not speak; so it was easy to pretend to be a deaf mute.
The Chief feels that the Combine has made him shrink in size. McMurphy promises the Chief that he will get him back to his original size and tells him “you growed half a feet already”. Mac asks Bromden to promise to lift the control panel when he is “big” again, and the Chief agrees. The Chief, seems to gain energy just talking to McMurphy, and before long he is even brave enough to turn down orders given by the orderlies
Most of Part III is centred on the fishing trip that McMurphy arranges for the patients. The Chief agrees to go on the fishing trip that McMurphy is planning and most of the other patients also agree to go along, in spite of Nurse Ratched’s trying to make them feel afraid by warning them about storms. The Doctor goes with them and McMurphy invites Candy Star and another prostitute to serve as a “chaperones”. On the way to the boat, McMurphy teaches the patients how to use their insanity to intimidate people When the patients set out, they are scared and lacking in confidence but because the patients really enjoy themselves – they catch fish, get drunk and have fun. They learn to be self-reliant and even withstand a storm. The fishing trip is an overall success.
The religious imagery that was introduced in Part I is further developed in Part III. When the patients are preparing to leave for the fishing trip, Ellis, the ‘crucified’ man, tells them to be “fishers of men,” the phrase used by Christ when asking his disciples to help convert people to Christianity. McMurphy, like Christ, has twelve followers.