Ibrahim bin Abi Khidash bin Utbah bin Abi Lahab says: I heard Ibn Abbas (may Allah be pleased with them both) saying about slaves: "Feed them with what you yourselves eat, and clothe them with what you yourselves wear."
Imam al-Shafi'i (may Allah have mercy on him) says: If someone cannot do this, that is, feed him on a par with himself, then let him do what the Prophet (peace and blessings be upon him) stated: provide for him in the customary manner (bil-ma'ruf). And al-ma'ruf in our view is the ordinary food and clothing of the town.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15779