If it’s a male leave him intact
You don’t want to do that. Intact males spray to mark their territory and that smells horrible, especially if you feed them dry food.
There is a significant difference between a feral and a stray. Ferals can’t tolerate the presence of a human and chances are high they can never be socialized and never trust a human.
Strays can accept the presence of humans and with time, can be socialized to one degree or another. If a cat will come out to eat in your presence, it’s a stray.
The rule of thumb is to feed a barn cat enough they’ll survive if they can’t catch prey and not so much they feel full. A hungry cat is a better hunter and easier to teach.
Make a big deal out of replenishing the auto feeder. Cats respect you more when they know you’re the source of food. An auto feeder set to dispense food at a certain time everyday will keep a cat close by. They’ll make it part of their routine to return to the feeder at that time to eat.
Keep a clean source of fresh water always available, especially when feeding dry food. Without fresh water, cats will develop urine crystals in their bladder which is very painful and can kill a cat. Cats get 75% of the water they need from their food and dry food provides none.
Cats are corpuscular which means they do most of their hunting at dawn and dusk.
Build a shelter to protect your barn cat from the elements. It doesn’t have to be large and should be placed where the cat can easily retreat to and defend itself if threatened by a predator such as a coyote and, can safely survey its territory. Cats that can survey their territory from a safe place is more confident, better at defending its territory and a better hunter. The shelter should at least be insulated against winter and padded inside.
Ferals & strays surviving on their own have a life expectancy of two years. For unsupervised outdoor cats under human care, it’s five years. Indoor/unsupervised outdoor cats last 7-9 years. Indoor cats that are allowed outside only while supervised have an average lifespan of 15-17 years with many living to reach 20 or more.
An intact female will attract Toms and populate your property with many kittens. Intact Toms will stink up the place with their spraying.