Why animal advocates should never, ever, advocate for mandatory spay-neuter laws: They do not work, they have never worked, they increase shelter killing, and they divert limited funding away from programs that actually do work to decrease shelter intake and increase lives saved.
This is not to say that additional spay/neuter isn't needed in most communities. It is. Rather, it is to say that passing mandatory spay/neuter ordinances isn't an effective way to achieve greater spay/neuter compliance rates. If you want to learn more about how to effectively decrease shelter intake and increase live outcomes, read the No Kill Equation here: http://www.nokilladvocacycenter.org/nokillequation.html. If you want to learn why mandatory spay/neuter laws are absolutely not the answer, read on.
Mandatory spay-neuter ordinances do not work. The ASPCA did an extensive study on mandatory spay-neuter laws and concluded that they have failed to decrease shelter intake. According to the ASPCA, there is no "credible evidence demonstrating a statistically significant enhancement in the reduction of shelter intake or euthanasia as a result of the implementation of a mandatory spay-neuter law." http://www.aspca.org/about-us/policy-positions/mandatory-spay-neuter-laws.html.
Mandatory spay-neuter ordinances target the wrong population. The largest category of animals entering the shelter are feral and community cats and their kittens. These are unowned or "loosely" owned animals who no person will claim ownership of. As a result, instead of targeting the population that needs spay-neuter (community cats), the ordinances target the population that largely is already spaying and neutering their animals to the tune of 80 or 85% (pet owners). Money is virtually thrown out the window by targeting pet owners rather than the unowned animals contributing most to shelter intake. The non-profit group Alley Cat Allies has a long article explaining this phenomenon. As Alley Cat Allies explains, "Mandatory spay/neuter laws do nothing to address the real issue[s].... Instead, these laws divert public resources away from beneficial programs and into administering an unenforceable law." http://www.alleycat.org/NetCommunity/Page.aspx?pid=794
Mandatory spay-neuter is extremely expensive. Enforcing the ordinance would require additional Animal Control officers and additional trucks and equipment. Just one employee and one truck would cost more than $100,000 in year one and more than $50,000 each additional year. Two would cost at least $200,000 to start. That money would come out of programs that work to save lives, like low-cost and free spay-neuter programs, Trap-Neuter-and-Release programs, foster programs for baby kittens, as well as adoption programs. In Los Angeles, mandatory spay-neuter required millions of dollars worth of additional funding at the cost of proven and workable solutions to shelter killing.
Mandatory spay-neuter laws kill more animals than they save. In Los Angeles, intake and shelter killing increased 30% after the City began enforcing its new mandatory spay-neuter program. In Kansas City, mandatory spay-neuter has been enforced by sweeps of poor neighborhoods, where healthy and loved dogs are handed over to Animal Control due to lack of funds for spay-neuter. Some cities (like Fort Worth, Texas) have abandoned their mandatory spay-neuter ordinances because the ordinances did not work.
Mandatory spay-neuter laws have negative and dangerous side effects. Cities such as Fort Worth, Texas, have experienced a decline in rabies vaccinations following implementation of mandatory spay/neuter ordinances. As a result, the public has become more at risk of rabies due to implementation of the ordinances. In addition, nearly every city to pass a mandatory spay-neuter ordinance has experienced a significant decrease in pet registrations, meaning that fewer pets who arrive at shelters are able to be reunited with their owners.
Mandatory spay-neuter laws unfairly target the poor. 90% or more of pet owners with the financial means to do so already spay or neuter their pets. The largest category of pet owners who haven't done so simply cannot afford to do so. For this group, cost--- not unwillingness--- is the primary obstacle to spay/neuter. As a result, Animal Control in Kansas City, for example, has done "sweeps" through poor neighborhoods picking up animals and killing them at Animal Control.
Mandatory spay-neuter laws promote backyard breeding and possibly even puppy mills. When Animal Control sweeps through a neighborhood and either seizes or, by "owner surrender" takes animals that families cannot afford to have spayed or neutered, families who lost their animals to the Animal Control authorities will replace it with another, feeding the backyard breeding industry and possibly even puppy mills.
Every major animal-welfare group who has studied the effects of mandatory spay-neuter laws is against them. The ASPCA is against them. So is Alley Cat Allies, the No Kill Advocacy Center, the American Veterinary Medical Association, and Best Friends Animal Society. We're not generally a group that defers to authority (and we're proud of it!), but the consensus against mandatory spay-neuter laws--- even among groups that rarely agree--- is highly compelling.