Abu Husayn (may Allah have mercy on him) said that Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both) saw among his sacrificial animals (hady) a she-camel blind in one eye, and he said: If the defect befell it after you bought it, then go ahead with it; and if it befell it before you bought it, then replace it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19195
Nafi' (may Allah have mercy on him) said that Abdullah bin Umar (may Allah be pleased with them both) used to say: Any man who sends a sacrificial animal (hady) and it goes astray: if it was a vow, he must replace it; and if it was voluntary, then if he wishes he replaces it, and if he wishes he leaves it.
Abdullah bin Amir al-Aslami narrated it from Nafi' as marfu' (from the Prophet), but the correct version is mawquf (a statement of Ibn Umar).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19196
Tamim bin Huways al-Misri said: I bought a sheep at Mina as a sacrifice, and it went astray. I asked Ibn Abbas (may Allah be pleased with them both) about it, and he said: It does not harm you.
Imam al-Shafi'i (may Allah have mercy on him) said: But if he finds it after having made it obligatory, he should slaughter it, even if the days of sacrifice have passed, just as is done with the sacrificial camels of the hady.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19197
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