What is the ruling on eating from a restaurant without the owner's permission? And is it permissible to sentence a thief to imprisonment and flogging for eating part of a chicken?

It is forbidden to eat from the restaurant owner's food without his permission, based on the Prophet's (peace be upon him) saying: "Indeed, your blood, your wealth, and your honor are sacred to you, as sacred as this day of yours, in this month of yours." As for the discretionary punishment (ta'zir), scholars differ concerning it, and the preponderant opinion is that the judge exercises his discretion regarding it according to what serves the best interest.