Feeding animals proteins derived from other animals might confuse some consumers, but chickens remain omnivores and can consume safe animal proteins without problems.
Poultry, and chickens in particular, as this discussion will focus on broilers and layers, are omnivorous animals. This implies that they eat practically “everything,” and this includes other animals — at least in their wild state. Farmed chickens are fed diets that we design for them to be complete, balanced, healthy and productive. As such, one of the most useful sources of protein is that of animal-derived ingredients. There is not as great a number of animal proteins as in the case of vegetable proteins, but the former have some unique properties or benefits not found in the latter. In many cases, it is even possible for the protein from animal-derived ingredients to be less expensive or more readily available than vegetable proteins. So, nutritionists are often faced with the dilemma of whether they should use animal proteins.