It used to be that eggs were just eggs. Perhaps you chose between brown and white, but there was little else to look for on the carton.

Thats changed. Consumers have more choices, but they come at a cost. Often, eggs with special features cage-free, vegetarian-fed, omega-3 enriched are at least twice the price of conventional eggs. The question is what are you getting for your money?

Below are explanations of some of the more common terms you will see on egg cartons. They can generally be divided into two categories: how the chickens are treated and the nutritional content of the eggs. Whether youre willing to shell out the extra cash is up to you.

Raising happier chickens

CAGE-FREE

Conventionally, egg-laying hens are raised in cages, often stacked one on top of another in crowded henhouses. Some animal rights groups have protested this treatment, and several states have passed laws requiring better treatment for the flocks.

Cage-free, as the name implies, means the chickens are not kept in cages but instead live in a henhouse and are free to move around that house. Usually, they are not allowed to go outside, nor are they fed anything different from hens kept in cages. Its based on the premise that a chicken allowed to roam has a better life.

I think people are generally under the impression that a free chicken would be happier, said Greg Satrum, an owner of Canby-based Willamette Egg Farms, which produces about 1.7 million eggs per day, some of them from cage-free hens. Its a public perception.

Objective measures, however, show letting the chickens out of their cages may not make them any more content. Caged hens, Satrum said, have lower mortality rates, higher production rates and dont have some of the behavioral issues found in those that roam. The more freedom you give them, the more freedom you give them for negative behaviors. They peck each other a lot more when loose.

In addition, the henhouses may not be quite as idyllic as the small farms many people imagine when they think cage-free. In her book What to Eat, New York University professor of nutrition Marion Nestle describes a tour of a cage-free henhouse. There, she writes, thousands of them were packed together in a crowded indoor space, flapping their clipped wings, fluttering on top of one another and clucking away.

At Willamette Egg Farms, said Satrum, chickens are given between 1.2 and 1.5 feet per hen. Its more room than many caged hens are given but not exactly space to stretch their wings.

FREE-RANGE

Free-range is different from cage-free in that chickens are not only kept outside of cages but are also given access to the outdoors.

The benefit is in how the hens are treated, said David Will, a general manager at Chino Valley Ranchers, a California-based large producer of free-range and other speciality eggs. Theres more opportunity to exercise and do what a chicken normally does.

Still, free-range chickens, like their cage-free counterparts, may not have the expansive coops that many people imagine. The chickens are not given access to the outdoors during certain times in their life, and the size of the outside area and the amount of time the birds are allowed outside is not standardized.

The whole free-range thing is kind of a misnomer, said Lori Brizee, a registered dietitian in Bend. The chickens arent running around on a farm.

Both cage-free and free-range hens are more expensive than conventionally raised eggs because they cost more to produce. Facilities for both are more expensive to install, said Satrum, and are less efficient to operate.

FREE-ROAMING

Theres no formal definition for free-roaming. It either means the hens are raised in a cage-free or free-range environment.

ORGANIC

Organic eggs are those raised with the strictest standards. Farms that use the U.S. Department of Agriculture Certified Organic label must comply with federal standards and are subject to inspections. These are also often the most expensive eggs.

According to the USDA, all organic animals must have access to the outdoors (which is why youll often see organic coupled with free-range on labels) and be given organic feed. They may not be given hormones to promote growth or antibiotics for any reason.

Compared with other ways of raising eggs, organic is the most expensive, Will said. Feed is the largest portion of cost. Its normally double to two-and-a-half times the cost of normal feed.

That food, said Will, contains no animal byproducts, including animal blood or bone bits.

In addition, at Chino Valley, the land that the chickens are raised on is certified organic as well, meaning there are no pesticides used on the ground.

Making more nutritious eggs

VEGETARIAN-FED

Vegetarian-fed chickens are not given any meat products. Conventionally, chickens eat feed made from soy or corn and animal byproducts, such as the scraps of beef or pig left over after the rest has been processed. There are varying opinions about the wisdom of all-vegetarian feed.

On one hand, chickens are naturally not vegetarians and are used to getting a bit of protein from animals. They eat a lot of bugs and stuff, Satrum said. We kind of chuckle about the vegetarian feed sometimes, but it appeals to some consumers.

On the other hand, an all-vegetarian feed could make the eggs healthier, say several local dietitians, by lowering the amount of saturated fat in the eggs. Saturated fat is a bad fat, linked to higher cholesterol and risks of heart disease.

Registered dietitian Vanessa Cobarrubia, who lives in Bend, said that the eggs laid by chickens that eat a vegetarian feed will have less saturated fat, although the differences are small.

ANTIBIOTIC FREE/HORMONE FREE

Chickens are rarely given either antibiotics or hormones, so these claims, though found on some cartons, are superfluous. For practical purposes, shoppers can think of all eggs as being free of antibiotics or hormones.

We kind of resisted putting that on our cartons because we thought it was a little misleading, Satrum said. But the perception is there that hormones are used.

In the egg industry, he said, no one is using hormones. Antibiotics are sometimes used for sick chickens, though not often. We havent used them in years.

OMEGA-3

Many premium egg cartons promise a higher dose of omega-3 fatty acids, those good fats that have been linked to a healthier heart and better brain development. A typical egg has between 30 and 40 milligrams of omega-3s, but some eggs boast 100 mg or higher.

Egg producers coax chickens into laying these premium eggs by feeding them food filled with omega-3s, often flaxseed. The food does have the effect of raising omega-3 levels in the eggs and, at least in the brand Consumer Reports tested in August 2004, the claims on the nutrition label about increased omega-3s were accurate.

Fish are a more concentrated source of omega-3s and dont come with the baggage of lots of extra cholesterol. Still, omega-3-enriched eggs can make your omelette just a little bit healthier.

I recommend the omega-3-enriched eggs, said Cobarrubia. But, she said, she also understood that people may not want to spring for the extra cost, particularly if they are getting omega-3 through supplements or another source. If you can afford it, then get one with omega-3, but if you cant, dont feel bad if you buy normal eggs, she said.

Even the run-of-the-mill, old-fashioned, commercially raised eggs are nutritious. Its a great source of vitamins and minerals, Cobarrubia said. Eggs are a great food.