According to Islamic scholars, if a chicken belonging to someone else lays an egg in your house and the owner is unknown, the egg is treated as a small lost item. This means it can be used without public announcement. This ruling is based on the fatwa that small lost items, which the owner would usually not search for, may be used. However, if the owner is later identified and asks for the value of the egg, it is necessary to return its price to the owner. This is the Islamic ruling given by scholars and supported by classical fiqh references.