I grew up in the middle of nowhere and feral cats showed up all the time on our farm. If there is a female cat, a male cat will find her. Even if you didn't have a male. Not judging, just trying to inform. I would get the male fixed asap, and there has to be a vet within driving distance. And if the female is pregnant I would have her spayed as soon as she is allowed after kittens are born. Good luck!
A cat in heat will drive you nuts. And the male will too when the female is in heat. Even in another house on your property you will hear them yowling and yes, they will stink up the house. Are you planning on putting litter boxes in the house for them or just leaving them to go where they may? And even if you let one out one day and the other out the next, the female will come into contact with a male on her days out. I guarantee it. Why do you think your traps or your dogs will catch any cat that comes on your property when you already have your barn cats roaming your property?
Sorry, I'm new here and probably should just shut up now.