Hi Donna,
What a caring person you and your colleagues are – helping these kitties! Thank-you on their behalf. I applaud your intention of preventing them from reproducing further. Feral cat overpopulation is actually quite a significant problem in Toronto and the GTA, and the more we can prevent this problem from growing, the better. These cats need to be vaccinated to help prevent the spread of disease (such as rabies, feline viral diseases, parasites, etc.), and spayed and neutered. It is also known that feral cats can also devastate wild migratory bird populations, contributing to the decline in important bird species.
There are a number of resources I would suggest you investigate. First, contacting the Ontario Society for the Prevention of Cruelty to Animals (OSPCA). Most regions in Ontario have their own branch. They may be able to help you connect with local resources for these kitties. Your municipal animal control or shelter may also be able to help you out. Some veterinary clinics operate their own shelter programs, often in partnership with a rescue or shelter. It would be worth calling or visiting your local vet clinics to see what they can do.
In Toronto, there are several organizations that run “Trap, Neuter, Release” programs for feral cat colonies. These programs involve trapping feral cats, vetting, vaccinating and sterilizing them, then releasing them back. The idea is to maintain the populations without allowing them to reproduce and spread disease, such that new populations cannot be established or grow. I do not know if there are any such organizations in your area (they tend to be in larger city centres), but it would be worth investigating. There may also be some independent animal or cat rescues that will be able to take care of these kittens.
I hope this is helpful.
Dr. Kim Hester