Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bukhari:6708Aḥmad b. Yūnus > Abū Shihāb > Ibn ʿAwn > Mujāhid > ʿAbd al-Raḥman b. Abū Laylá > Kaʿb b. ʿUjrah

I came to the Prophet ﷺ and he said to me, "Come near." So I went near to him and he said, "Are your lice troubling you?" I replied, "Yes." He said, "(Shave your head and) make expiation in the form of fasting, Sadaqa (giving in charity), or offering a sacrifice." (The sub-narrator) Aiyub said, "Fasting should be for three days, and the Nusuk (sacrifice) is to be a sheep, and the Sadaqa is to be given to six poor persons."  

البخاري:٦٧٠٨حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ حَدَّثَنَا أَبُو شِهَابٍ عَنِ ابْنِ عَوْنٍ عَنْ مُجَاهِدٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى عَنْ كَعْبِ بْنِ عُجْرَةَ قَالَ

أَتَيْتُهُ يَعْنِي النَّبِيَّ ﷺ فَقَالَ ادْنُ فَدَنَوْتُ فَقَالَ أَيُؤْذِيكَ هَوَامُّكَ قُلْتُ نَعَمْ قَالَ فِدْيَةٌ مِنْ صِيَامٍ أَوْ صَدَقَةٍ أَوْ نُسُكٍ وَأَخْبَرَنِي ابْنُ عَوْنٍ عَنْ أَيُّوبَ قَالَ صِيَامُ ثَلاَثَةِ أَيَّامٍ وَالنُّسُكُ شَاةٌ وَالْمَسَاكِينُ سِتَّةٌ