Hadith 8:3027
Abu Bakr narrated to us, he said: Ibn Idris narrated to us, from Hisham, from al-Hasan, he said: He should slaughter it while it is kneeling, for it is easier for it and for the one who is slaughtering it.
حدثنا أبو بكر قال نا بن إدريس عن هشام عن الحسن قال ينحرها وهي باركة وهو أهون عليها وعلى من ينحرها