More than 12,500 have now signed a petition which was first launched after concerns for a group of horses in Wellingborough.
Concerns have been raised about the horses in and around Wellingborough's Embankment for many years, with people regularly raising the issue with the RSPCA and the Northants Telegraph.
Campaigners from the Help For Wellingborough Horses group launched an online petition calling for action as they felt the horses were not being looked after properly.
While the RSPCA carried out a huge rescue of 43 horses from the site in February, the petition is still gaining names on a daily basis and the total of signatures now stands at more than 12,550.
The petition is calling for changes to the Animal Welfare Act.
It states: "According to law, the way most horses are treated and kept is acceptable, therefore the RSPCA cannot remove them. This law needs changing."
Campaigners believe the law is very basic in what is said in the code of practice regarding horses' welfare and treatment, including a suitable environment, suitable diet and to exhibit normal behaviour patterns
And the petition goes on to say: "These laws are not stating the standards of the animals environment, not stating the standards of a suitable diet and are not suitable for 'animal welfare'.
"The law leaves the 'codes of practice' open to debate and opinion, meaning horses can be neglected and owners can disagree - since the law is open to interpretation.
"What you consider to be a suitable environment may not be considered a suitable environment to me.
"Therefore, we are calling on the law to set standards higher, with more detail on what is acceptable and what's not, and what will happen to people who break the laws."
Earlier this week, the RSPCA warned that a recession could plunge the country into a second wave of 'the equine crisis' which has already led to thousands of sick horses being dumped by their owners.
In 2019, the charity received reports of more than 4,241 incidents involving horses in the Midlands, 364 of those in Northamptonshire.
Since lockdown, the RSPCA has received 29 reports about horses in Northamptonshire, but fears much worse is to come if, as expected, the Covid crisis sparks a recession.