What is the ruling on chicken that is fed frozen blood added to its feed to increase protein and chicken growth?

If the predominant food of chickens or other edible animals is najis (impure), they are considered "jallalah" and must be confined until they become pure. However, if the najis food is minimal (20-30%), it does not affect them and does not render them unlawful. An animal is considered jallalah if the proportion of najis food is 60-70% or more. Chickens are confined for three days, while sheep and cattle are confined for seven days or more, during which they are fed pure food until their meat becomes pure.