Found this interesting Article Poultry Talk. It is one of the many good articles of the Wellness Letter which relies on the expertise of the School of Public Health and other researchers at University of California, Berkeley, as well as other top scientists from around the world. If you don't have time to surf over there, here is a brief summary of what is in that article:
Eating white meat (chicken or turkey) is better than eating red meat as poultry has less fat and fewer calories, especially if the skin is removed. However, the healthiest diets are still diets rich in fruits, vegetables, and whole grains (and include some fish) and lower in animal products of all kinds.
What’s the difference between farm-raised and organic chicken? Well, organic chicken are raised on 100% organic feed and no antibiotic is used, plus the welfare of the chicken have to be promoted (a rather vague provision). However, slaughtering methods are the same no matter how the chicken was raised, and that’s where most contamination with Salmonella and Campylobacter, two potentially deadly strains of bacteria found in raw chicken, occurs.
The free-range label means the birds have access to an outdoor pen, via portals on the poultry house. They may never go outdoors, and you shouldn’t picture them roaming free in a big yard. “Pastured” chickens, sometimes sold in high-end markets, are also raised in cages, but the cages sit on grass and are moved from time to time. There is no evidence that chickens labeled “free-range” or “pastured” taste better, are more nutritious, or get more humane treatment than other birds.