Here's a little list that may help with your selection, I got it from here
http://www.acreaturecomfort.com/ratingpetfood.htm
How to grade your pet's food:
Start with a grade of 100:
1) For every listing of "by-product", subtract 10 points
2) For every non-specific animal source ("meat" or "poultry", meat, meal or fat -not actual protein source stated such as chicken, lamb, turkey etc) reference, subtract 10 points
3) If the food contains BHA, BHT, or ethoxyquin, subtract 10 points for each
4) For every grain "mill run" or non-specific grain source, subtract 5 points
5) If the same grain ingredient is used 2 or more times in the first five ingredients (I.e. "ground brown rice", "brewers rice", "rice flour" are all the same grain), subtract 5 points
6) If the meat protein sources are not in the top 3 ingredients, subtract 3 points
7) If it contains any artificial colorants or preservatives, subtract 3 points for each
8 ) If it contains corn (ground corn, corn gluten, whole grain corn etc) subtract 3points
9) If corn is listed in the top 5 ingredients, subtract 2 more points
10) If the food contains any added animal fat other than fish or flaxseed oil, subtract 2 points
11) If it contains soy or soybeans, subtract 2 points
13) If it contains wheat or a component of wheat such as gluten, subtract 3 points
14) If it contains "digest" subtract 5 points
15) If it contains salt, subtract 1 point
Extra Credits:
Bonus credit-If the food contains NO grains, add 10 points
1) If any of the meat sources are organic, add 5 points
2) If the protein source is meal vs meat, add 5 points
3) If the food is baked not extruded, add 5 points
4) If the food contains probiotics or prebiotics, add 3 points
5) If the food contains fruit, add 3 points
6) If the food contains vegetables (NOT corn or other grains), add 3 points
7) If the animal sources are hormone-free and antibiotic-free, add 2 points (these may be hard to determine as many manufacturers of natural holistic food use these products without actually printing the information on the bag)
8 ) If the food contains barley, add 2 points
9) If the food contains flax seed oil (not just the seeds), add 2points
10) If the food contains oats or oatmeal, add 1 point
11) If the food contains sunflower oil, add 1 point
12) For every different specific animal protein source (other than the first one; count "chicken" and "chicken meal" as only one protein source, but "chicken" and "" as 2 different sources), add 1 point
13) If it contains glucosamine and chondroitin, add 1 point
14) If the vegetables are pesticide-free, add 1 point
Score:
100+ = A+ 94-100=A 86-93 = B 76-85 = C 75 or lower= Failed
And here's a quick explanation of some ingredients:
Animal Digest: This is the dry by-product of rendered meat. During rendering, all usable animal parts (including fetal tissues and glandular wastes) are heated in vats and the liquid is separated from the dry meal. This meal is covered with charcoal and labeled "unfit for human consumption" before processing it into pet food. Digest can also include intestines, as well as the contents of those intestines, such as stool, bile, parasites and chemicals.
Animal Fat and Tallow: Animal fat is a "generic" fat source that is most often made up of rendered animal fat, rancid restaurant grease or other oils that are deemed inedible for humans. Tallow is low quality hard white fat that most animals find hard to digest, not to mention the cardiac risks resulting.
Chemical Preservatives: Chemical preservatives include BHA (butylated hydroxyanisole), BHT (butylated hydroxytolulene), propyl gallate, propylene glycol (also used in automotive antifreeze and is suspected of causing red blood cell damage) and ethoxquin , are all potentially cancer causing agents that your pets are eating every day.
Chicken By-products: These are ground parts from poultry carcasses such as feet, heads, feathers, intestines, necks and undeveloped eggs and can included any rendered material.
Corn Products: Corn products including corn meal, gluten and grits are cheap, allergy causing fillers and are very difficult for animals to digest.
Food Fragments: Lower end by-products of the food manufacturing process, examples include wheat bran and brewers rice which are a waste product of the alcohol industry.
Ground Whole Grain Sorghum: The feed value of grain sorghum is similar to corn and is grown primarily as a feed grain for livestock.
Meat and Bone Meal: “Meat” and bone meal are inexpensive sources of animal protein. Note that these companies do not clarify the source of “meat”, nor are they human-grade meat. The protein in Meat meal containing a large amount of processed bone may not be digestible and fail to provide adequate nutrition.
Meat Based: A label that say "meat based" may also include blood vessels, tendons, organs and other parts of the rendered animal. Note again that these companies do not clarify the source of “meat”, nor are they human-grade meat products.
Meat By-products: Pet grade meat by-products consist of organs and parts not desired or not fit for human consumption. This can include organs, bones, blood and fatty tissue. It can also include brains, feet, heads, intestines and any other internal parts. Unbelievably, by-products can also contain cancerous or diseased tissue containing parasites, euthanized animals, .