My three cats are indoor/outdoor and are kept in at night due to coyotes in the area. They are bird friendly and don't bother my birds. One of my geese likes to give one of my cats a hard time.
 
But I do have a feral cat in the neighborhood. He pretty much sticks to the perimeter of the yard and has not interacted with my domestic cats. Since my birds are protected I do not worry about him getting to them. He has been severely injured at some point and is basically three legged (front right looks crooked and he doesn't use it). This feral is a true survivor to have stayed alive this long (almost a year) and since he has been no trouble I let him be. I have (unfortunately) had to have a feral humanly dispatched because it was a threat to both my livestock and domestic cats. I felt terrible but had to be done. The friendlier cats get taken to shelters. My neighborhood seems to be a dumping ground for unwanted cats. I've kept two of them after a full vet checkup, worming, shots, and neutering.