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Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
muslim:2119b – Muḥammad b. al-Muthanná > Muḥammad b. Jaʿfar > Shuʿbah > Hishām b. Zayd > Anas

So far as I know (he was cauterising) their ears.  

مسلم:٢١١٩b – حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ حَدَّثَنَا شُعْبَةُ عَنْ هِشَامِ بْنِ زَيْدٍ قَالَ سَمِعْتُ أَنَسًا يُحَدِّثُ

أَنَّ أُمَّهُ حِينَ وَلَدَتِ انْطَلَقُوا بِالصَّبِيِّ إِلَى النَّبِيِّ ﷺ يُحَنِّكُهُ قَالَ فَإِذَا النَّبِيُّ ﷺ فِي مِرْبَدٍ يَسِمُ غَنَمًا قَالَ شُعْبَةُ وَأَكْثَرُ عِلْمِي أَنَّهُ قَالَ فِي آذَانِهَا  

See similar narrations below:

Collected by Aḥmad, Ibn Ḥibbān
ahmad:12750 – Muḥammad b. Jaʿfar > Shuʿbah > Hishām b. Zayd > Anas b. Mālik

So far as I know (he was cauterising) their ears. (Using translation from Muslim 2119b)  

أحمد:١٢٧٥٠ – حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ حَدَّثَنَا شُعْبَةُ عَنْ هِشَامِ بْنِ زَيْدٍ قَالَ سَمِعْتُ أَنَسَ بْنَ مَالِكٍ يُحَدِّثُ

أَنَّ أُمَّهُ حِينَ وَلَدَتْ انْطَلَقُوا بِالصَّبِيِّ إِلَى النَّبِيِّ ﷺ لِيُحَنِّكَهُ قَالَ فَإِذَا النَّبِيُّ ﷺ فِي مِرْبَدٍ يَسِمُ غَنَمًا قَالَ شُعْبَةُ وَأَكْبَرُ عِلْمِي أَنَّهُ قَالَ فِي آذَانِهَا  

ذِكْرُ الْإِبَاحَةِ لِلْمَرْءِ أَنْ يَسِمَ ذَوَاتِ الْأَرْبَعِ فِي غَيْرِ الْوَجْهِ

ibnhibban:5629 – Muḥammad b. Isḥāq b. Ibrāhīm a freed slave of Thaqīf > Yaʿqūb b. Ibrāhīm al-Dawraqī > Bahz b. Asad > Shuʿbah > Hishām b. Zayd b. Anas > Anas b. Mālik

[Machine] "I came to the Messenger of Allah ﷺ with a brother who wanted you to breastfeed him. I found him in the scalding pot while he was boiling sheep. Shu'bah said: I am most certain that he said it in her ears."  

ابن حبّان:٥٦٢٩ – أَخْبَرَنَا مُحَمَّدُ بْنُ إِسْحَاقَ بْنِ إِبْرَاهِيمَ مَوْلَى ثَقِيفٍ قَالَ حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ الدَّوْرَقِيُّ قَالَ حَدَّثَنَا بَهْزُ بْنُ أَسَدٍ قَالَ حَدَّثَنَا شُعْبَةُ قَالَ حَدَّثَنَا هِشَامُ بْنُ زَيْدِ بْنِ أَنَسٍ عَنْ أَنَسِ بْنِ مَالِكٍ قَالَ

«أَتَيْتُ رَسُولَ اللَّهِ ﷺ بِأَخٍ لِي يُرِيدُ أَنْ يُحَنِّكَهُ فَوَجَدْتُهُ فِي الْمِرْبَدِ وَهُوَ يَسِمُ غَنَمًا قَالَ شُعْبَةُ أَكْثَرُ ظَنِّي أَنَّهُ قَالَ فِي آذَانِهَا»