He asked the Messenger of Allah ﷺ about hunting, and he replied, "When you release your dog, mention the name of Allah over it. If you catch the prey before it has been killed, slaughter it and mention the name of Allah over it. If you find it already killed and the dog has not eaten any of it, then eat from it, for the dog has held it for you. But if you find that the dog has eaten from it, do not eat any of it, for the dog has only held it for itself. And if your dog mingles with other dogs and they kill the prey but do not eat from it, do not eat any of it, for you do not know which of them made the kill."
أخبرنا الإمام أبو عبد الرحمن النسائي بمصر قراءة عليه وأنا أسمع عن سويد بن نصر قال أنبأنا عبد الله بن المبارك عن عاصم عن الشعبي
أنه سأل رسول الله ﷺ عن الصيد فقال إذا أرسلت كلبك فاذكر اسم الله عليه فإن أدركته لم يقتل فاذبح واذكر اسم الله عليه وإن أدركته قد قتل ولم يأكل فكل فقد أمسكه عليك فإن وجدته قد أكل منه فلا تطعم منه شيئا فإنما أمسك على نفسه وإن خالط كلبك كلابا فقتلن فلم يأكلن فلا تأكل منه شيئا فإنك لا تدري أيها قتل
Reported by Muslim, Hunting and Slaughtered Animals, chapter, "Hunting with trained dogs and shooting," hadith 7/1929, from the hadith of Ibn Mubarak, and by Bukhari, Slaughtered Animals and Hunting, chapter, "When the game disappears for two or three days," hadith 5484, from the hadith of Asim al-Ahwal through him, and it is in Al-Kubra, hadith 4774.