I will chime in here and say that Purina is a low grade dog food. I've done my homework when it comes to dog food because I have 2 dogs with food allergies- to corn, soy, wheat, oats, and barley. My beagle Socket is also very intolerant/sensitive to chicken meat/meal in dog foods.
Here is some information that I have from a different labrador forum that I'm a member of:
Choosing a new dog food can be an overwhelming decision. Learning to read the label on the bag can go a long way toward helping you decide.
The following guidelines are courtesy of Whole Dog Journal:
*One or more named meats(Chicken, Lamb, etc.) in the first few ingredients (or a named meat and a named meat meal)
*Whole foods (i.e. rice rather than brewer's rice, corn vs. corn gluten meal)
*No unnamed animal sources (i.e. Animal Fat, Meat and bone meal)
*No artificial colors or flavors
*No chemical preservatives (i.e. BHA, BHT, ethoxyquin)
*No added sugars or artificial sweeteners
Here's also a website that grades dog foods by their ingredients, etc.
http://www.thepetfoodlist.com/petfoods_pg1.htm
Hope this helps. Feel free to message me if you want some advice/suggestions.
I'm going to dig up some info that I have on coprophagia (poo eating) and see what I can find. There are things that you can add to the dog food to discourage the eating of feces.