Does chicken droppings and urine remain pure if the chicken feeds on leftover meat, mortadella, and animal feed?

The droppings of birds whose meat is permissible to eat, such as chickens, are considered pure by the majority of jurists, whether they come into contact with the body or the garment. They do not invalidate the prayer nor do they defile the garment. Some jurists made an exception for the droppings of domestic chickens and ducks if most of their diet consists of impure substances, in which case their droppings would be impure. In such a case, eating their meat and eggs would be prohibited unless they are subsequently fed pure food for three days or more. As for the Shafi'is, most of them stated that bird droppings are impure absolutely, but they issued a fatwa allowing for their pardon in prayer due to the difficulty of avoiding them.