Qasim bin Muhammad (may Allah have mercy on him) said that Sayyidah Aishah (may Allah be pleased with her) drove two sacrificial camels, which went astray. So Abdullah bin al-Zubayr (may Allah be pleased with them both) sent her two camels in their place, and she slaughtered them. Then she found the first two and slaughtered them as well. Then she said: This is the Sunnah regarding sacrificial camels.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19198