Is allowed to sacrifice on the second and third days after Eid-ul-Adha. And how many days does Eid-ul-Adha last - is it just 1 day or 3 days?
You can sacrifice 3 days after the Eid day (total 4 days).
Ibn al-Qayyim (may Allaah have mercy on him) said in Zaad al-Ma’aad (2/319):
‘Ali ibn Abi Taalib (may Allaah have mercy on him) said: “The days of sacrifice are the Day of Sacrifice (yawm al-nahr) and the three days after it.”