If you are concerned about your family's health, good taste or the humane treatment of animals, today's American supermarket can be a pretty confusing place. Labels such as "100 percent natural," "organic," "grain-fed," and "free range" are everywhere, but what do these terms really mean?

The U.S. Department of Agriculture (USDA) says, "100 percent natural" means the poultry does not contain preservatives or other "artificial ingredients". But experts will tell you that there are no guarantees.

"No inspections are done. So we don't know if those claims are really true," says Shannon Wallace, R.D., registered dietitian with Baylor University Medical Center at Dallas.

Chicken labeled as "organic" must meet much stricter standards. Inspections are conducted and organic chicken cannot contain artificial ingredients, hormones or antibiotics. According to Ms. Wallace, however, "the USDA does not make any claims that organically produced food is any safer or more nutritious than conventionally produced food."

Some chickens carry the label "grain fed." Once again, there is no independent monitoring for this claim. The same is true for "free range."

"Free range does not always mean that the animal has been in an open area its whole life. It may only mean they were in a restricted area and let out into that open area one time during their life," says Wallace.

The one way to be certain? Raise the birds yourself.