If you've ever bought eggs in a supermarket, you've probably faced this conundrum: do I buy the regular, cheap eggs, or the nicer, organic/cage-free eggs? And supposing you want to spring for the humane stuff, how do you know which farms are really treating their hens right, and which are just throwing up smoke and mirrors?

The short answer: yes, you should be buying cage-free eggs. But the case for buying organic or free-range eggs isn't very compelling. When shopping around, be sure to look for "Certified Humane" and, even better, "Animal Welfare Approved" stickers on your eggs. They're your best bet if you love egg products but want to be sure the hens laying them are being treated well.

Why cage-free matters

Most eggs are produced in a way that severely hurts chickens. About 97 percent of egg-laying hens in the United States are confined to what are known as "battery cages," holding 5 to 10 birds each, with United Egg Producers' minimum standards mandating 67 square inches per bird — a smaller space than a standard 8.5-by-11-inch piece of paper (UEP estimates that about 15 percent of hens are raised by farmers that don't even meet those standards).

These spaces severely disrupt the laying process, causing huge pain to birds. "The worst torture to which a battery hen is exposed is the inability to retire somewhere for the laying act," the Nobel laureate ethologist Konrad Lorenz once said. "For the person who knows something about animals it is truly heart-rending to watch how a chicken tries again and again to crawl beneath her fellow cagemates to search there in vain for cover."

There are three broad alternatives to traditional cages: barn systems, aviary systems, and "enriched cages." The following illustration from the book Compassion by the Pound by researchers F. Bailey Norwood and Jayson L. Lusk shows how the four options compare:

In barn systems, a large flock gets an entire barn within which to roam freely, with food and water provided at various locations, perches available, sawdust for scratching, and nests for hen to lay in, usually with a curtain to provide privacy for the hen. Norwood and Lusk estimate that the typical barn provides 200 square inches per bird, nearly triple the amount given to battery caged hens.

Aviaries are like barns, but with multiple floors at different heights that birds can fly or walk up to. That might give the birds more space, depending on the floor space allotted, and it makes it easier for them to run away from bullies in the flock. Both aviaries and barns can provide access to the outdoors, making them "free range" systems. In the enriched cage system, birds are still in cages but get "more space, a small perch, a pan for dust bathing, and a private nest for egg laying."

There are some disadvantages to the barn/aviary cage-free approach. Most significantly, mortality is significantly higher: Norwood and Lusk estimate that the mortality rate in cage systems is 3 percent, while it's 7 percent for cage-free, 9 percent for free-range, and 13 percent for organic. At first glance, that's a point in favor of an enriched cage approach, not a cage-free approach.

It's not clear how much of this is due to differences in confinement conditions, and how much is just due to differences in the type of chicken being raised in each environment. Brown hens tend to work better in cage-free environments, whereas white hens are preferred by cage-egg producers, for example, and experiments have found that when raised in identical environments, brown hens have higher mortality rates anyway.

But in practice, what's causing the deaths doesn't really matter. Buying more cage-free eggs these days means bringing into existence more brown hens with shorter lives and fewer white hens with longer lives; you have to weigh that against the higher quality of life the brown hens get while they exist.

Luckily, there are relatively rigorous ways to weigh those factors. One is FOWEL, a mathematical model used to estimate the welfare of laying hens under various conditions on a scale of 0 to 10, 10 being the best. Norwood and Lusk report that FOWEL gives the typical cage system a 0.0, enriched cages 2.3, aviaries 5.8, barns 5.9, and barns with free-range provisions 6.3.

So cage-free is better than caged. And this matters not just at a macro level, but when it comes to individuals' spending decisions about eggs. The level of egg production — and thus the number of hens who suffer through this — is highly responsive to changes in consumer spending: 0.91 fewer eggs are produced for every egg not consumed, per Norwood and Lusk, as farms birth fewer hens into these awful conditions. Put another way, each caged egg you don't eat prevents about a day of chicken suffering by helping reduce the number of chickens who are raised for this kind of treatment.

What about organics and free-range eggs?

The brown hen/white hen divide isn't the only thing accounting for differences in mortality rates, though. Free-range birds and organic birds face even higher death rates than non-free-range cage-free birds, and those differences probably are a consequence of differences in how the animals are treated. Free-range birds are at very real risk of predation, which leads to them registering similar stress levels as caged birds. They also face a greater danger from parasites.

This can be overcome to some degree through predator protection measures like tall wire fencing, but merely knowing that eggs are "free range" doesn't tell you that the hens had that kind of safety. "The desirability of any free range system depends crucially on predator protection and the indoor housing facilities provided," Norwood and Lusk conclude. They argue for considering free range an "optional component" of cage-free production.

In other words: don't go actively looking for free-range eggs. Cage-free alone is good, and in some cases even better than free range.

Producers of organic eggs in the US have to provide some outdoor access, raising similar concerns as non-organic free-range eggs; they must be cage-free as well. But organic producers also aren't allowed to provide synthetic amino acids to chickens (even though those acids significantly improve chickens' nutrition and overall health), and are restricted in their usage of antibiotics.

"A farmer cannot treat a sick animal with antibiotics and then sell the animal for organic food," Norwood and Lusk write. "This causes some farmers to deny antibiotics to sick animals. As a result, hens suffer. A number of animal scientists in the US believe organic production is cruel to hens for this reason."

Add in the fact that organic eggs aren't any better for you — just like most organic foods — and you have a pretty good case for preferring non-organic cage-free eggs to organic ones. Organic's still better than caged eggs, to be sure, but the policies toward antibiotics and amino acids are cruel.

What stickers should I be looking for?

The most rigorous animal welfare certification program when it comes to eggs is Animal Welfare Approved. Their logo is a white sun with blue rays over a green pasture:

As the Humane Society of the United States explains, AWA has the highest standards of any private animal welfare auditing program for eggs. It prohibits producers from beak cutting, in which farmers remove part of newborn hens' beaks to prevent pecking, and from starving birds to force them to molt, another unfortunately common practice. But AWA-approved eggs can be hard to come by. There aren't any stores selling AWA eggs within a 15 mile radius of Washington, DC, for example.

A second-best option is Certified Humane, which bans forced molting but not beak cutting. Both AWA and Certified Humane free range require outdoor access, for better or worse (Certified Humane has different levels of certification; the basic level doesn't require outdoor access). Certified Humane is a lot easier to find in the grocery store, with brands like Nellie's and Open Nature making the cut. The logo is pretty easy to spot:

"American Humane Certified" and "Food Alliance Certified" offer similar protections as Certified Humane. "United Egg Producers Certified" is a much weaker certification; it bans forced molting but allows for hens to be kept in cages. "Pasture-raised" means much the same thing as "free range" labels. And a lot of common labels tell you nothing at all about chicken treatment: vegetarian-fed, natural, farm fresh, fertile, omega-3 enriched, pasteurized, etc.

Why ethically raised eggs might not be good enough

That said, many animal advocates would urge consumers to not just buy better eggs but to reduce egg consumption in general. One reason is that a lot of the eggs we eat don't take the form of eggs we buy in cartons, but come in mayonnaise, salad dressings, frozen foods, restaurant meals, and other contexts where it's hard to judge where the eggs came from, and what conditions the hens were raised in.

More importantly, though, most hatcheries that supply hens to farms — even cage-free or free-range farms — use a practice called "chick culling," in which male chicks are slaughtered en masse, usually by grinding them alive:

Gassing is also sometimes used. This is not an inevitability of egg production. The use of dual-purpose breeds of chicken, where the males could be (humanely) raised for meat rather than killed immediately, eliminates the need for culling; so does identifying chick gender inside the egg, which new technological developments have made possible. Two years ago, United Egg Producers committed to eliminating culling by the year 2020 using in-ovo sex detection. But until then, culling is still a reality of American egg production, one to which people eating eggs today are contributing.

Cage-free eggs are definitely better. There's no doubt about that. But eating fewer eggs altogether is better still.

Correction: An earlier version of this article said that all Certified Humane certifications require outdoor access; only some do.