Amr bin Shurahbil narrates from Sayyidah Aishah (may Allah be pleased with her) that she said: We had a goat that was about to die, so we slaughtered it and distributed it. Then the Prophet (peace and blessings be upon him) asked: "What became of your goat?" She said: It was about to die, so we slaughtered it and distributed its meat; only a shoulder of it remains. He (peace and blessings be upon him) said: "The whole goat is yours except the shoulder."
(b) Al-Zuhri narrates from Ibn al-Musayyib (may Allah have mercy on him) that slaughter is valid even while the eye and the tail are moving and the leg is also moving.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيد والذبائح / 18958