Allah, the Blessed and Exalted, said concerning slave-women: "And when they are married, then if they commit an indecency, upon them is half of the punishment that is upon free (married) women." [Surah al-Nisa: 25]
Imam al-Shafi'i (may Allah have mercy on him) said: "Half can only be in the punishment of flogging, which can be divided; as for stoning, which is killing, it has no half."
He (further) said: "And the Messenger of Allah (peace and blessings be upon him) said: 'When the slave-woman of one of you commits zina and her zina becomes clear, let him flog her.' And he (peace and blessings be upon him) did not say that he should stone her."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / Q17086
Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "When a slave-woman commits zina and her zina becomes clear, flog her with the prescribed punishment and do not reproach her. If she commits zina a second time, flog her again; if she commits zina a third time, sell her, even if you sell her for a rope of hair."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17086
Abdullah bin Ayyash al-Makhzumi (may Allah be pleased with him) said: Sayyiduna Umar (may Allah be pleased with him) ordered me, together with some young men of Quraysh, and we flogged slave-girls of the state fifty lashes each for zina.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17089
Sayyiduna Ali (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "When your slave-women commit zina, carry out the hadd on them, whether they are married or not."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17090
Abu Habibah said: I came to Sayyiduna Ali (may Allah be pleased with him) and said: I have committed zina, so carry out the hadd on me. He turned me away four times, then said: O Qanbar! Give him the hadd of a hundred lashes. I said: I am a slave. He said: Flog him, and when I say so, stop. Then he gave him fifty lashes.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17092
Ma'qil bin Muqarrin (may Allah be pleased with him) came to Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) and said: My slave has stolen a cloak from my (other) slave. He said: Your property has stolen your property. And he mentioned his slave-girl, that she had committed zina. He said: Flog her. He said: She is not muhsan (married). He said: Her Islam is her ihsan.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17093
Thumamah bin Abdullah bin Anas (may Allah have mercy on him) said: I came to Sayyiduna Anas (may Allah be pleased with him) while he was flogging a slave-girl for zina. Whether married or unmarried, he would flog them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17094
Al-Sha'bi (may Allah have mercy on him) said: The ihsan of a slave-woman is her entering Islam and affirming it; when she has entered Islam and affirmed it and then commits zina, she is to receive fifty lashes. Ibrahim (may Allah have mercy on him) interprets "when they are muhsan" [Surah al-Nisa: 25] as becoming Muslim, and Mujahid (may Allah have mercy on him) as marriage, and he says: If she has not been married, there is no hadd upon her. Mujahid (may Allah have mercy on him) also narrates the like of this from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17095