Musnad Ahmad 627:22

Yahya ibn Adam narrated to us, Isra'il narrated to us, from Mansur, from Ibrahim, from Hammam ibn al-Harith, from 'Adi ibn Hatim, who said: I asked the Prophet, peace and blessings of Allah be upon him, and said: "O Messenger of Allah, we send our trained dogs." He said: "Eat." I said: "Even if they kill [the game]?" He said: "Even if they kill, as long as no other dogs share with them." I said: "We shoot with the *mi'rad* (a blunt-headed arrow)." He said: "If it pierces, then eat, and if it strikes with its side, then do not eat."