The huge beef recall spurred recently by claims that livestock were being mistreated has drawn the public's attention to the welfare of farm animals.

There already are labels on many eggs, meat and poultry brands in the grocery store that aim to inform consumers about how animals are fed, what they're fed and how they're raised. But while these labels all seem positive, few are clearly defined.

Free-range, free-farmed, rBGH-Free, certified organic, cage-free, certified humane. What do they all mean? Figuring them out is difficult, made even more difficult by convoluted government regulations.

Below are some of the most commonly used terms, their definitions and how reliable they are, according to the Humane Society of the United States and certifying agencies. It is hoped this guide will help you make better informed choices on your next shopping trip.

Certified Organic: Birds must be uncaged inside barns or warehouses. While they are technically required to have outdoor access, the parameters are unclear and sometimes meaningless. Chickens are fed an organic, all-vegetarian diet free of antibiotics and pesticides. Beak trimming to prevent birds from harming each other or themselves is permitted and commonly used. Forced molting through starvation to increase egg production is permitted. Compliance is verified through third-party auditing.

Certified Humane: The birds are uncaged inside barns or warehouses, but may be kept indoors at all times. They must be able to perform natural behaviors such as nesting, perching, and dust bathing. There are requirements for density -- the number of hens in a given space -- and number of perches and nesting boxes. Forced molting through starvation is prohibited, but beak cutting is allowed. Third-party auditing verifies compliance.

Cage-Free: Hens must be uncaged inside barns or warehouses, but outdoor access is not required. There are no required standards for density. Beak cutting and forced molting through starvation are permitted. There is no third-party auditing.

Free-Range or Free-Roaming: The U.S. Department of Agriculture has not set standards for "free-range" egg production. Hens are probably uncaged inside barns or warehouses and can probably engage in many natural behaviors. There are no density requirements; forced molting through starvation is permitted, as is beak trimming.

United Egg Producers Certified: The United Egg Producers is an industry-sponsored organization. According to its Web site, 95 percent of U.S. eggs come from farmers certified by this organization. The organization makes some claims regarding animal welfare. Forced molting through starvation is prohibited, and third-party auditing guarantees that hens receive "sufficient space, nutritious feed, clean water, proper lighting and fresh air," and that hens can "groom, lie down, stand, stretch, turn around and engage in other behaviors." However, hens' movements are too restricted for them to engage in many other normal behaviors, hens can be fed animal-based products and the ultimate goal of the United Egg Producers is to produce the maximum number of safe, low-cost eggs; not, in other words, to minimize animal suffering or maximize quality of life.

Certified Organic: The animals must be allowed outdoor access, with ruminants -- cows, sheep and goats -- given access to pasture. Unfortunately, wide parameters have led to some lax enforcement concerning outdoor space. Animals must be provided with bedding materials. Use of hormones and antibiotics is prohibited. Third-party auditing verifies producers compliance to regulations.

Certified Humane or Free Farmed: Animals' conditions must allow for exercise and freedom of movement, so crates, cages and tethers are prohibited. Outdoor access is not required. Stocking densities are specified to ensure animals are not overcrowded, and animals must be provided with bedding materials. Use of hormones and non-therapeutic antibiotic use are prohibited. Third-party auditing verifies compliance.

Pasture-Raised and Grass-Fed: The animals have access to the outdoors and are able to engage in natural behaviors, such as grazing. However, neither stocking density, frequency, duration of outdoor access nor quality of the land is regulated. Producers must submit affidavits to the USDA that support their animal production claims to use these labels.

Hormone-Free, rBGH-Free, rBST-Free and No Hormones Added:

Growth hormones are commonly used to speed growth in beef production. While the use of these hormones has been approved by federal regulatory groups, there is no scientific consensus about their long-term effects on the environment or on human health.

Producers may not legally give chicken or pigs hormones.

Grain-Fed or Corn-Fed: Ruminants do not naturally eat grain, and their stomachs are not designed to handle it. So, feeding them grain can cause liver abscesses and problems with lameness. In addition, cows raised on grain (especially corn) are higher in saturated fat and lower in omega-3 fats than cows raised on grass.