You don't see bison as much as cows but it is not uncommon.
As for the ingredients lists people are showing, the first on the list is what it has the most of an the last is what it has the least of. That does not mean that if the first thing on the list is chicken then its mostly chicken. It could be less than 5% chicken. The longer the ingredients list the more likely there is actually very little of the first ingredient in the product.
Ingredients:
Chicken, Chicken Meal, Cracked Pearled Barley, Millet, Brewers Rice, Chicken Fat (Preserved with Mixed Tocopherols), Beet Pulp, Natural Chicken Flavor, Flaxseed, Fish Meal, Potassium Chloride, Salt, Choline Chloride, Dried Chicory Root, Glucosamine Hydrochloride, Vitamin E Supplement, Iron Proteinate, Zinc Proteinate, Yucca Schidigera Extract, Copper Proteinate, Ferrous Sulfate, Zinc Sulfate, Copper Sulfate, Potassium Iodide, Thiamine Mononitrate, Manganese Proteinate, Manganous Oxide, Chondroitin Sulfate, Ascorbic Acid, Vitamin A Supplement, Biotin, Calcium Pantothenate, Manganese Sulfate, Sodium Selenite, Pyridoxine Hydrochloride (Vitamin B6), Vitamin B12 Supplement, Riboflavin, Vitamin D Supplement, Folic Acid.
This list has 42 ingredients so even tho it says chicken first it may be less than 3% chicken. I also have to ask why if it has chicken in it then why does it need "Natural Chicken Flavor." The amount of actual chicken in there must be very low to have to add "Natural Chicken Flavor" to hide the taste of all the junk so the dogs will eat it....
Ask your self why the ingredients list are so long an why each ingredient is in there...