In a massive victory for animal rights activists, and for America's chickens, United Egg Producers, a group that represents 95 percent of all eggs produced in the United States, has announced that it will eliminate culling of male chicks at hatcheries where egg-laying hens are born by 2020.

This may sound like a technical development, but its magnitude in humanitarian terms is difficult to overstate. That's because standard practice at hatcheries that supply egg farms with hens is to kill almost all male chicks shortly after birth, usually by grinding them to death, as you can see in this horrifying video:

Gassing is also sometimes used. Hundreds of millions of male chicks are killed this way, every year, in the United States alone.

The business logic behind chick culling is hard to get around. There's no reason to keep the male chicks alive; they're not useful for meat, as broiler chickens are bred in a totally different manner, to maximize size and quantity of meat. In the past, animal welfare advocates have proposed breeding "dual-purpose" chickens, which could be raised humanely for meat as well as serving as hens, to get around this, but got little traction.

But ending chick culling has become possible recently due to technology. United Egg Producers says it will replace culling with "in-ovo egg sexing." This is a process that can determine the sex of chicks before they develop inside their egg. That enables egg producers to terminate the male eggs and potentially use them to help make vaccines or for pet food (most humans would presumably be grossed out by cooking fertilized eggs). Horrific infanticides will be replaced with humane, painless chicken abortions.

Unilever became the first major corporation to take a stand against culling in 2014, declaring its intention to use in-ovo egg selection to avoid chick culling in hatcheries where the hens that lay eggs for Ben & Jerry's, Hellman's Mayonnaise, and its other egg-based products are born. In Germany, where much of the research enabling in-ovo sexing took place, policymakers committed last year to use the technology to eliminate chick culling by 2017.

Government action in the US hasn't been forthcoming, but these new UEP policy changes — which follow negotiations with the Humane League, a relatively young but shockingly effective and influential animal rights organization — are the next best thing.

In a statement, Humane League executive director David Coman-Hidy stated that the UEP commitment "will virtually eliminate this practice in the American egg industry. … It is clear that chick culling will soon be a thing of the past in the United States."

This solidifies the Humane League as one of America's most important animal rights groups

The Humane League (THL) does not have the public recognition that groups like PETA or the Humane Society of the United States do, but it's quickly become one of the most important and effective voices for animals in the United States. It was founded relatively recently, in 2005, and until very recently had only a handful of staffers. But it soon figured out a very effective way of making progress: corporate campaigns. It lobbies companies that buy large quantities of meat and eggs to demand higher animal welfare standards from their suppliers.

This really works. For example, THL contacted colleges and universities that employ the food services company Sodexo, along with students at those colleges and universities, and asked them to demand that Sodexo only use cage-free eggs. Eventually, Sodexo committed to do just that. And THL did all this at very low cost.

"Up until a year ago, THL had achieved 2-4 corporate victories per year with two part-time staff working on corporate campaigns," the Open Philanthropy Project wrote in an analysis earlier this year. "Since putting four full-time staff on corporate campaigns a year ago, THL has achieved about 35 victories."

"These are all standard tactics," Coman-Hidy told me in an interview last year. "But with only a few people and a few laptops, we could replicate the work over and over with new clients each week, and that was what made the campaign. Sodexo lasted two months. … If you perfect your tactics, it costs almost nothing. Getting 54 companies was done by three or four people with laptops,"

In total, the Open Philanthropy Project estimated that THL spent less than $250,000 on corporate campaigns and, estimating very roughly, spared about 300 hens from cage confinement for every dollar spent. Even if that estimate is off by an order of magnitude, it's a very impressive figure.

These negotiations on chick culling will have an even bigger impact. If the changes stick, THL's activism will have prevented the deaths of literally millions of chicks going forward, at roughly no cost. "For the Humane League, the cost is solely our time put into the conversations," Jessie Lingenfelter at THL tells me. That is impact of just an astonishing scale.

Undercover videos help explain meat in America