Is it permissible to feed ducks the remains of birds ritually slaughtered, such as intestines, knowing that some feeds contain such ingredients?

If the feed ingredients for ducks or other animals whose meat is permissible to eat are pure, then there is no harm in feeding them to the animal and consuming its meat after slaughtering it, unless this causes harm, in which case it is prohibited, due to the Prophet’s (peace be upon him) saying: “There should be neither harming nor reciprocating harm.”