What is the ruling on working in marketing to increase the sales of "KFC" and "McDonald's" restaurants, which are said to be Western?

It is permissible to market sales for fast-food restaurants if they are free from prohibitions and the meat is slaughtered according to Islamic methods. However, if they include prohibited items, then marketing them must be avoided, based on the Almighty's saying: "And cooperate not in sin and aggression," and based on the Prophet's (peace be upon him) saying: "Indeed, Allah Almighty, when He forbids the eating of something, He also forbids its price." If there is doubt about the permissibility of its sales, it is best to refrain from marketing it. It is recommended to avoid marketing for such restaurants due to the frequent reports regarding their violation of Sharia in their slaughtering methods.