What is the ruling on sacrifices where "Bismillahi wa Allahu Akbar" is written on the wall, but not uttered verbally, except by personal diligence?

Chicken slaughtered according to Islamic law is permissible if the slaughterer is a Muslim or a person of the Book, due to the verse: "The food of those who were given the Scripture is lawful for you." However, that which is killed by strangulation or electric shock is not permissible. The pronouncement of "Basmalah" (in the name of Allah) and "Takbir" (Allah is the Greatest) is not required if the slaughterer is a person of the Book, but it is required that no name other than Allah's be mentioned over it. If the slaughterer is a Muslim, scholars differed on the requirement of "Basmalah": Imam Al-Shafi'i does not require it, the Malikis and Hanafis require it for one who is able and remembers, and Imam Ahmad requires it absolutely. Writing "Bismillah, Allahu Akbar" on the wall has no effect.