The SunFresh line of Purina poultry products is all "vegetarian", as we have a significant customer base that does not want to feed animal proteins or fats to their birds. However, we have other brands (Home Grown, Country Acres) that may use animal proteins and fats. There is no doubt that, nutritionally, animal proteins are a much more complete source of the amino acids required in the diets of birds than are plant proteins. Vegetarian poultry diets are supplemented with individual amino acids to make sure these needs are met, and the bird's body really does not care if the amino acid is synthetically or naturally derived. The higher the protein (and therefore specific amino acid) requirement of the bird, the more supplemental amino acids must be added to vegetarian diets to meet the bird's requirements if animal proteins are not used. However, research has shown that equal performance can be attained using either type of feed, so it really boils down to the personal preference of the customer. Chickens are omnivores, meaning they eat both animal and plant foods, so they have no problem adapting to either type of diet.