Here's a great opportunity to explore all the phrases that appear on poultry labels: free-range, organic, natural, pasture-raised, grass-fed, etc. Many of these terms are not regulated by the U.S. Department of Agriculture and, thus, have no real legal meaning.

An exception is organic. The USDA's National Organic Program states that "organic meat, poultry, eggs, and dairy products come from animals that are given no antibiotics or growth hormones." Organic food is produced without using most conventional pesticides, synthetic fertilizers, bioengineering or radiation. And it must be certified by a USDA-approved inspector.

The USDA's Food Service and Inspection Service (FSIS) compels producers of so-called free-range poultry to demonstrate that the birds in question have "been allowed access to the outside." Natural poultry contains no artificial ingredients or added color and is only minimally processed.

And that's it for USDA regulations.

Now, the department also publishes a document called US Trade Descriptions for Poultry that outlines voluntary trade standards for chicken and chicken products. The trade descriptions specify six categories of poultry, each one comprising a production method (where the birds live) and a feeding system (what the birds eat).