The Messenger of Allah ﷺ said, "Do not sacrifice anything but a mature animal, unless that proves difficult for you, in which case you may sacrifice a young sheep."
حدثنا أحمد بن أبي شعيب الحراني حدثنا زهير بن معاوية حدثنا أبو الزبير
قال رسول الله ﷺ لا تذبحوا إلا مسنة إلا أن يعسر عليكم فتذبحوا جذعة من الضأن
Muslim narrated it in the Book of Udhiya, Chapter on the Age of the Udhiya, hadith no. 1963, from the hadith of Zuhayr bin Muawiya, with this chain. And the explicit mention of Abu Zubayr's hearing appears in Sahih Abu Awana, 5/228.