Some non-Muslims cut off the ears of some animals and set them free to roam anywhere making no use of them thereafter. Is it permissible for a Muslim to slaughter and eat these animals?
If the situation is as you mention and no harm results from taking them, it is permissible to take these animals and eat from them if they are slaughtered in a Shar`y (Islamic legal) way and their meat is lawful. Furthermore, taking such animals may be obligatory, if a person can take them, for it is a form of removing Munkar (that which is unacceptable or disapproved of by Islamic law and Muslims of sound intellect) and striving to eliminate Shirk (associating others with Allah in His Divinity or worship).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.