I will tell you that we tried to adopt through the OSPCA (Ontario Society for the Prevention of Cruelty to Animals) back in 2014 when we were looking for 2 more cats and were DECLINED because we wanted to keep them in the barn. I was furious!
Our barn is a warm, happy place and the cats are well fed and loved. Update - since about 2016 they have changed their policy and many SPCAs have a Barn Cat Adoption Program.
All of our cats have been spayed/neutered and vaccinated. Although the neighbours joke that we have the most expensive barn cats around, cats that are fixed and tend to wander less and have less disease than their unneutered counterparts.
In March 2019, our local OSPCA began a low cost, high volume spay neuter program. Versus our veterinarian office, we have saved over $100/each with the neuter of our new Livestock Guardian dog and 3 newest barn kittens (late 2018 & 2022).