Is it prohibited for a person who is going to do Udhiyah (Qurbani) to cut hair and nails in the first 10 days of Dhul Hijjah?
It is not prohibited (Haraam) to cut the hair and nails in the first 10 days of Dhul Hijjah for a person intending to perform Udhiyah (Qurbani), however, it is recommended (Mandoob) not to according to the Hanafi Madhab. In a Hadith in Sahih Muslim, Sayidah Umm Salamah reported that the Prophet ﷺ said:
عَنْ أُمِّ سَلَمَةَ، تَرْفَعُهُ، قَالَ: إِذَا دَخَلَ الْعَشْرُ وَعِنْدَهُ أُضْحِيَّةٌ يُرِيدُ أَنْ يُضَحِّيَ، فَلَا يَأْخُذَنَّ شَعْرًا، وَلَا يَقْلِمَنَّ ظُفُرًا
When the ten days begin, and one of you has a sacrificial animal and he intends to sacrifice it, then he should not cut his hair or nails.Sahih Muslim, 1977 – 40
This Hadith is understood to be referring to the recommendation of not cutting the hair and clipping the nails and not an absolute prohibition of doing so. This is the understanding of the Hanafi Madhab. In Radd al-Muhtar, after quoting the above hadith in Sahih Muslim, Ibn Abideen says:
فَهَذَا مَحْمُولٌ عَلَى النَّدْبِ دُونَ الْوُجُوبِ بِالْإِجْمَاعِ
This is considered to be a recommendation and not an obligation by consensus.Ibn Abideen, Radd al-Muhtar Vol. 5, p.154
And Allah Subhanahu Wa Ta’ala knows best.