Sa'id bin Jubayr (may Allah have mercy on him) said: If a slave woman commits adultery, she is not to be flogged the prescribed punishment until she marries. So I asked Abd al-Rahman bin Abi Layla (may Allah have mercy on him), and he said: I found the remaining ones of the Ansar beating a slave woman from among their slave women in their gatherings when she committed adultery.
Imam al-Shafi'i (may Allah have mercy on him) said: Sayyiduna Ibn Mas'ud (may Allah be pleased with him) used to order it, and Sayyiduna Abu Barzah (may Allah be pleased with him) did apply the prescribed punishment.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17110