There are already studies out there that prove free range chickens with wide variety of food or specialty feed produce more healthy eggs. You don't have to produce your own studies. There are also ones that show the commerical 'cage free' eggs are of dubious nutritional value since many do not allow enough room for the chickens to truly roam and get some exercise.
Yes I love countryside (right now let you know more in a year when I have more experience with them). Their ingredient list follows:
INGREDIENTS
Organic Field Peas, Organic Corn, Organic Wheat, Organic Oats, Fish Meal, Organic Rice Bran, Organic Alfalfa Meal, Organic Flaxseed, Calcium Carbonate, Sodium Silico Aluminate, Dried Organic Kelp, Dicalcium Phosphate, Salt, Yeast Culture, Roughage Product (organic wheat middlings), Vitamin A Supplement, Vitamin D3 Supplement, Vitamin E Supplement, Choline Chloride, Menadione Nicotinamide Bisulfite Complex, D-Calcium Pantothenic Acid, Niacin Supplement, Riboflavin Supplement, Pyridoxine Hydrochloride, Thiamine Hydrochloride, Vitamin B12 Supplement, Biotin, Folic Acid, Manganese Sulfate, Ferrous Sulfate, Calcium Iodate, Zinc Sulfate, Copper Sulfate, Sodium Selenite, Dried Aspergillus oryzae Fermentation Extract, Saccharomyces cerevisiae, Dried fermentation product of Lactobacillus acidophilus, Dried fermentation product of Lactobacillus casei, , Dried fermentation product of Lactobacillus plantarum, Dried fermentation product of Enterococcus faecium, Dried fermentation product of Bacillus coagulans, Dried fermentation product of Bacillus licheniformis, and Dried fermentation product of Bacillus subtilis.