Sayyiduna Jabir (may Allah be pleased with him) says: The Prophet (peace and blessings be upon him) was asked about a person who shaved his head before stoning, or stoned before shaving his head, or sacrificed before shaving his head. He (peace and blessings be upon him) said: "Do it, and there is no harm."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9631