This is a somewhat controversial ingredient in the food industry but there is no solid evidence to suggest that it is a harmful ingredient. (pawster.com)
Pork by - products and Chicken by - products are included in this dog food as protein sources and they are considered as controversial ingredients. (dogfoodselector.com)
However, we find that both the wet and dry versions of this brand contain a number of controversial ingredients that offer little nutritional value for dogs. (petfoodtalk.com)