How is ageism shown in the book Of Mice and Men?

Candy is an old cripple that most of the ranchers show prejudiced against for being old. Consequently, he himself can't be dishonest and lie about his age 'I ain't got the poop any more'. Secondly Steinbeck also shows ageism through the progression of the novel by Candy having a friend at the beginning and, as the story gets on, he loses his friend to Carlson.