From the brutal pounds of the 1800s to the no-kill revolution — how America learned to value every animal
On April 10, 1866, the New York State Legislature passed a law creating the American Society for the Prevention of Cruelty to Animals. Henry Bergh, a diplomat's son who had been horrified by what he witnessed in the streets of New York and St. Petersburg, had spent years lobbying for it. The ASPCA was the first animal protection organization in the Western Hemisphere, and its founding moment is as close as the animal welfare movement has to a clear origin point.
Bergh understood that the problem was systemic. The streets of mid-nineteenth century American cities were filled with stray animals — dogs, cats, horses, pigs — in numbers that are difficult to imagine from the vantage point of the present. The response of city governments was the pound: a facility whose purpose was not to shelter animals but to remove them from public spaces. Animals were held briefly and then killed, usually by methods selected for cheapness rather than humaneness. The pound was a sanitation tool, not a welfare institution.
The ASPCA's early work focused primarily on horses and farm animals — the most visibly abused animals in an urban economy that ran on animal labor. But Bergh's foundational insight — that animals were not property to be treated arbitrarily but beings with interests deserving legal protection — would eventually reach every corner of the animal welfare question, including the question of what to do with the millions of dogs and cats that had no home.
Three years after Bergh founded the ASPCA, a Quaker reformer named Caroline Earle White established the Women's SPCA of Pennsylvania in Philadelphia. White had been refused a seat on the ASPCA's board because of her sex — a barrier she responded to by founding her own organization. The Women's SPCA introduced something the ASPCA had not: a formal adoption program.
White's organization built a shelter — the first building in the United States designed specifically to house stray and abandoned animals with the explicit goal of finding them new homes. It was a radical departure from the pound model. Instead of managing strays as a public health problem to be eliminated, White framed them as a welfare problem to be solved through placement. The shelter she built in Philadelphia operated on the belief that a homeless animal deserved both temporary safety and a permanent home — an assumption so foundational today that it is nearly invisible, but which required active argument and institutional invention to establish in 1869.
White also campaigned against the use of painful killing methods in pounds and shelters, advocating for lethal gas chambers as a (humane) alternative to drowning, beating, or starvation. This reflects the genuine complexity of the history: people who were, by the standards of their time, genuine reformers and animal advocates championed practices that we now recognize as deeply inadequate. The moral baseline kept moving, and the movement kept being forced to move with it.
By the mid-twentieth century, American animal shelters were killing animals at a scale that is difficult to fully absorb. Estimates suggest that in the 1970s, approximately 20 million animals were killed in US shelters annually — in a country with a total dog and cat population of perhaps 70 million. For every two to three pet animals living in homes, roughly one was being killed in a shelter each year.
The methods used across this period shifted several times under pressure from reformers. Gas chambers — carbon monoxide or carbon dioxide — replaced cruder methods in many facilities. Electrocution was used in some jurisdictions. Lethal injection with sodium pentobarbital, advocated by the Humane Society of the United States beginning in the 1970s, became the standard endorsed by major veterinary and animal welfare organizations as the most humane available option — though its requirement for trained personnel and controlled substances created implementation barriers that kept cruder methods in use longer than reformers wanted.
The kill rate was driven by arithmetic that seemed, at the time, insurmountable. Animals came in faster than they could be placed. Resources for care were limited. Holding capacity had physical limits. The killing of (unadoptable) animals — a category defined broadly enough to include shy dogs, older cats, and anything requiring medical treatment — was treated as not merely acceptable but necessary. The moral alternative, keeping every animal alive until placement, was dismissed as economically impossible and practically naive.
In 1994, Richard Avanzino became president of the San Francisco SPCA and made a decision that the shelter world considered either visionary or deluded: he declared that the San Francisco SPCA would no longer kill any healthy or treatable animal. The city of San Francisco, in partnership with the SPCA, would work to achieve a (no-kill) standard — saving every animal who could be saved.
The declaration was not a fantasy. Avanzino had spent years building the programs and community partnerships that made it operationally achievable: high-volume adoption events, foster networks, community outreach, targeted spay-neuter subsidies, behavior rehabilitation for dogs who would previously have been deemed unadoptable. San Francisco became the first major American city to achieve no-kill status for healthy and treatable animals. It demonstrated that the arithmetic was not, in fact, fixed — that with sufficient program infrastructure and community investment, the numbers could be made to work.
Nathan Winograd, who had worked under Avanzino, systematized the lessons into what he called the No-Kill Equation — a framework published in his 2003 book Redemption that identified 11 specific programs whose simultaneous implementation produced no-kill outcomes in any community. The programs included high-volume low-cost spay-neuter, foster networks, rescue group partnerships, active community outreach, medical and behavioral rehabilitation, and the fundamental shift from a (holding facility) model to an (adoption organization) model. Winograd argued — and his data increasingly supported — that the killing of healthy and treatable animals was not a resource constraint but a choice, and that communities which made the different choice achieved different outcomes.
The transformation of the shelter landscape between 1970 and 2022 represents one of the most significant — and least celebrated — social policy achievements in recent American history. From approximately 20 million animals killed annually in the 1970s, the number fell to an estimated 800,000 in 2022. In raw percentage terms, the kill rate dropped by more than 95 percent over five decades.
This transformation had multiple drivers. The spay-neuter movement, which began gaining significant momentum in the 1970s and 1980s, reduced the supply of homeless animals by addressing reproduction at the source. Microchipping, which became widely available in the 1990s and 2000s, enabled shelters to return lost pets to their owners at rates that were previously impossible — some studies suggest microchipping doubled the return-to-owner rate for dogs. The no-kill movement restructured shelters' self-understanding from waste management facilities to adoption organizations.
The trap-neuter-return (TNR) approach to community cats — feral and free-roaming cats who cannot be socialized for adoption — generated significant controversy within the animal welfare community, with some organizations maintaining that TNR enabled ecological damage to bird populations and others arguing it was the only humane and effective approach to feral cat populations. That debate continues, often with considerable heat, to this day.
Breed-specific legislation — municipal laws banning or restricting ownership of specific breeds, typically Pit Bull-type dogs, Rottweilers, and Dobermans — created another fault line in the shelter world. Banned breeds flooded shelters in jurisdictions with BSL, were disproportionately killed, and studies consistently failed to show that the legislation reduced dog bite incidents. The trend among major animal welfare organizations has been to oppose BSL as both ineffective and counterproductive, though enforcement of existing laws in some jurisdictions continues.
The COVID-19 pandemic of 2020 produced what shelter workers described as an unprecedented surge in pet adoption. Quarantined households, working from home, suddenly wanted companionship. Shelters that had spent years struggling with overcrowding found themselves in the novel position of running low on available animals. Rescue organizations flew dogs from overcrowded Southern states to under-supplied Northern shelters. The phrase (adopt don't shop) achieved mainstream cultural penetration it had never previously enjoyed.
The aftermath was harder. By 2022 and 2023, as work-from-home arrangements ended and pandemic-era lifestyle changes reversed, shelters began seeing surrender rates spike. Pandemic puppies whose owners had not anticipated the realities of full-time dog ownership. Cats adopted during lockdowns who had never been properly socialized. Animals with behavioral problems that had developed during two years of limited social exposure. Shelter populations climbed back toward pre-pandemic levels in many regions, and some systems reached crisis conditions.
The shelter movement entered 2024 facing a familiar tension: between the genuine progress of the no-kill philosophy and the persistent structural conditions — poverty, housing instability, inadequate low-cost veterinary access, insufficient spay-neuter infrastructure — that continued to drive animals into shelters faster than the system could absorb them with full commitment to every life.
Henry Bergh's 1866 insight — that animals had interests deserving legal protection — has grown, over 158 years, into a movement that has saved tens of millions of lives and continues to evolve toward its own stated standard. The work is not finished. But the direction of travel, measured across the full arc of the history, is unmistakable.
To learn about some of the breeds most commonly found in shelters, visit our dogs and cats breed guides. And if you're thinking about adding a pet to your family, our care guides can help you prepare.
When was the ASPCA founded, and what was its original purpose? The ASPCA was founded by Henry Bergh in New York on April 10, 1866, making it the first animal protection organization in the Western Hemisphere. Its original mandate focused primarily on preventing cruelty to work animals — horses, in particular — in a city whose economy depended heavily on animal labor. The scope of its work expanded over subsequent decades to include companion animals.
What is the No-Kill Equation? The No-Kill Equation is a framework developed by Nathan Winograd, based on his work under San Francisco SPCA president Richard Avanzino, that identifies 11 specific programs whose simultaneous implementation produces no-kill outcomes. These include high-volume spay-neuter, foster networks, rescue partnerships, community outreach, and medical and behavioral rehabilitation. Winograd argues that communities achieving these programs consistently reach no-kill status regardless of geographic or demographic conditions.
How many animals are killed in US shelters today compared to the 1970s? Estimates suggest approximately 20 million animals were killed in US shelters annually in the 1970s. By 2022, that number had fallen to approximately 800,000 — a reduction of more than 95 percent over five decades, driven by the spay-neuter movement, the no-kill philosophy, microchipping, and changes in adoption culture.
What is trap-neuter-return (TNR) and why is it controversial? TNR is an approach to managing feral cat populations in which cats are humanely trapped, surgically sterilized, vaccinated, and returned to their outdoor territories. Proponents argue it is more humane and effective than culling, which has been shown to produce only temporary reductions in population through the vacuum effect. Critics argue that outdoor cats cause significant damage to bird populations and that TNR enables a harmful ecological dynamic. Major animal welfare organizations generally support TNR, while some conservation groups oppose it.