What is the ruling on eating birds or fish that feed on filth, and what is the ruling on investing in such foods?

If an animal eats impurities and the taste, color, or smell of its meat changes as a result, it falls under the ruling of an animal that feeds on filth (Jallalah), and it is not permissible to eat it until it has been fed pure feed for a sufficient period for its meat to become wholesome again. However, if the consumption of impurities was incidental or for a short period and its meat did not change, it is not considered Jallalah, and it is permissible to eat it, while the prohibition of feeding it impurities remains. If an animal is determined to be forbidden due to being Jallalah, it is not permissible to invest in foods made from its meat, just as it is not permissible to invest in it even if the meat has not changed, if it is said that feeding the animal impurities is forbidden.