I have been researching through numerous books and stories about what influenced John Updike to write his short story, "A&P"?
All of Updike's writing deals with middle-class American values and their relationship to religion, sexuality, marriage, and divorce. In 1961, Updike said he got the idea for this story when driving by an A & P, and he wondered why no one had written about what goes on inside such a place, which is an important part of middle-class life. He had also seen some girls shopping in an A & P in bathing suits, and he thought they looked "naked" in their skimpy attire. He wondered what would happen if religious, middle-class Americans disapproved of shoppers dressed in such clothing, and the result was "A & P". He then created his protagonist who fights for the girls' rights to shop in their bathing suits. So Updike was inspired by driving around his home town of Ipswich, Massachusetts, proving that art reflects reality.
John Updike frequently wrote for "The New Yorker", a magazine that was read by many people who were culturally and artistically sophisticated. This often dictated HOW he composed his pieces--using a lot of symbolism and literary devices (such as irony, alliteration, allusion and the like).
John Updike was raised as a Lutheran, hence the many references to sheep in the story. His Lutheran background may also have something to do with the main character's desire to break free and rebel from social constraints.