Hey Sonoma County, how well do you know your eggs?

Shopping for eggs at the local supermarket has gotten complicated enough to make your head spin. Cage-free. Farm fresh. Natural. Pasture-raised. Organic. Free range. Prices that can range from $2 a dozen to as high as $9.99. Tack on the various sizes and grades, and a dozen different brand names, and the result is a dizzying array.

Navigating the options requires deciding what matters most to you - whether it’s value, nutritional content, sustainability concerns or the humane treatment of the laying hens - and learning how to recognize it on the shelf.

Arnie Riebli, a Petaluma egg farmer for 50 years, chalks the increasing options up to consumer demand.

“In the last 20 years, and much more in the last five or six, organic and cage-free have really come into play,” said Riebli, a partner in Petaluma’s Sunrise Farms. “Before that, 99 percent of all eggs produced and consumed were conventional.”

Sunrise Farms now produces eight different types of eggs - including organic, cage-free and conventional - but don’t try to shop for them under the Sunrise Farms brand name. All of the company’s eggs are supplied to private labels across Northern California, including Costco’s Kirkland brand.

Shopping by price can be just as confusing. While you can buy a carton of conventionally produced eggs at Target for about $2.99 a dozen, the organic version will cost at least $5 a dozen. At some stores, pasture-raised eggs from local farmers can run up to $9.99 a dozen - when you can find them.

The “cage free” label refers to the way in which hens are housed while they are laying their eggs. In 2008, California voters passed Proposition 2, requiring state farmers to provide all egg-laying hens with the ability to stand up, lie down, turn around and fully extend their wings. The concept got national buzz in 2015 when McDonald’s announced it would begin using only 100 percent cage free eggs within the next few years, and Trader Joe’s announced that it would sell only cage-free by 2025.

Most egg producers complying with Prop. 2 replaced traditional cases with “vertical indoor aviary systems” in which birds have access to multi-tiered nesting and perching levels inside a barn. Still, the label does not mean chickens are guaranteed access to the outdoors. In fact, a certified cage free egg might come from a chicken that has never been outside.

Consumers looking for eggs from hens that spend at least part of their life outdoors must look for the “free-range” and “pastured” labels.

To qualify as free-range, hens must be provided with outdoor access for a minimum of six hours a day, with at least a few square feet of space per bird. Of course, that outdoor space might just be a brown dusty square of earth.

Pasture-raised hens, on the other hand, are required to have access to greener pastures. Look for the Humane Farm Animal Care label, a certification that means the animals spend a minimum of six hours every day on rotated, vegetarian-covered pastures.

Consumer demand for pastured and free-range eggs is on the rise, said Joseph Stanley, the buyer for Costco’s Northern California region dairy departments, but the supply, at least in California, is scarce.

“It’s very tight,” Stanley said. “I’m sourcing from a lot of places to find those eggs. We have to look outside of California because there is not even close to enough production here.”

Yet cage free and organic currently account for about 8 percent of egg production in the United States, according to United Egg Producers.

What about the other labels? According to the Humane Society of the United States, the following have no relevance to animal welfare: vegetarian-fed, natural, farm fresh, fertile, Omega-3 enriched, and pasteurized. The labels “farm fresh” and “natural,” in particular, are not regulated by the USDA. They can be slapped onto cartons by egg producers without oversight, lending them little credence.

As for natural? Well, all eggs are natural, so take it with a grain of salt. “Raised without hormones” fits into this category as well since most eggs, even conventionally raised ones, are produced without added hormones. Vegetarian-fed just means that hens are being fed a strict vegetarian diet, with no meat or fish products. For Omega-3 enriched, the hens have been fed a special vegetarian diet, usually fortified with flaxseed.

What about the grade and size of the egg? Do they matter?

The grade of a shell egg (AA, A, B) is determined by the size of the internal air cell, according to the Egg Safety and Quality Management Program in the California Dept. of Food and Agriculture. Basically, the higher the grade, the bigger the yolk. Higher grades must also have a clean, unblemished shell appearance. Blemished or dirty eggs are given a B grade, to be used in the pasteurized liquid egg mixtures at fast food restaurants and the like.

Registered egg graders assess eggs not only for grade but size, whether small, medium, large or jumbo. Eggs are then classified by weight by the dozen. Most recipes call for large eggs, and it’s important to heed this warning, lest you end up with dry baked goods. While an extra-large egg yields about 4 tablespoons of white and yolk, a medium egg yields only about 3 tablespoons.

Finally, any egg expert will agree that brown eggs are no healthier than white eggs. Chickens with white feathers produce white eggs, and chickens with red feathers produce brown eggs, that much is true, but there is no difference in the nutritional makeup.

Still, people are prone to think of brown eggs as healthier because they more closely resemble the eggs produced by backyard chickens, and because a dozen usually costs more. Why? Because brown-egg producing hens are larger, meaning they eat more.

In terms of nutrition, look at what the hens eat rather than the color the egg, advises Dr. Daphne Miller, a family physician in Berkeley and a senior adviser at the Prevention Institution. She points to a recent study by an Italian university that compared the quality of eggs from hens raised conventionally in cages, on organic mash in a high-density barn and on organic pasture. The findings showed that pasture-raised hens laid eggs, especially in the spring, with “significantly” more beta-carotene, flavonoids and healthy Omega-3 fats than the hens in cages or free-range organic barns.

“I recommend pasture-raised eggs to my patients,” said Miller. “The price point is higher, but you get much more nutrition per dollar spent.”

Leilani Clark is a Sonoma County-based freelance writer.