Is it permissible to eat chicken whose method of slaughter is unknown due to the unavailability of chicken slaughtered in the Islamic way in the city, while there is lamb and beef sold by a Muslim whose level of commitment is unknown, but who claims to slaughter according to Islamic law?

If it is known that chickens in a certain city are not slaughtered according to Islamic law (dhakah shar'iyyah), then it is not permissible to buy them, as they are considered unlawful carrion (maytah), except in cases of extreme necessity, such as fear of death. However, if the method of slaughter is unknown, and those responsible for it are Muslims or People of the Book, then it is permissible, because the food of the People of the Book is lawful for Muslims, unless it is known that they slaughtered it in a manner not compliant with Islamic law. In case of doubt regarding the slaughter, it is preferable to avoid it. There is no harm in buying meat slaughtered by a Muslim, even if their level of adherence to religious practice is unknown, because the default ruling for the sacrifices of Muslims and the People of the Book is permissibility.