1, poor sales: KFC evaluated the sales of the breakfast and found that it did not sell as well as expected, so it decided to take it off the shelves.

2. Seasonal adjustment: KFC will adjust the breakfast menu according to seasonal factors. For example, in the summer, people prefer simple, light breakfasts, so KFC will take down some of the greasier or higher calorie breakfast options.

3. End of campaign: KFC's $6 breakfast was part of a certain promotion, and when the campaign ended, the breakfast was taken off the shelves.