Recently we took in a feral cat which had been live-trapped. The people who had caught this big Tom were concerned that he would fight and possibly kill the resident cats who lived in their barn. He had shown up at their place several weeks ago, no doubt attracted by the scent of cat food. It's not unusual for Toms to kill kittens, even their own, because of a primeval urge to establish and maintain the pecking order. The cat was taken to the veterinary service where it was examined, neutered and vaccinated. Just attempting to extricate the big fellow from the cage proved to be a formidable challenge, not to mention handling a terrified bundle of claws and teeth which had likely never felt a human touch.
That was a week or so ago. The big guy is crouching in the very back of his cage which is covered by a blanket to provide him with a quiet space to lessen his anxiety level. The staff speak softly to him and open the cage door to feed him and clean his litter box; so far he is still shrinking into his corner as far as he can with his ears and whiskers flattened. He makes no attempt to approach the hand that is feeding him. At least he is not attacking. Now what to do with him? It will take more than a few weeks to get him to the point of trusting that these humans are not going to hurt him.
He can't be kept in a cage for the rest of his life so at some point he will need to be released. When feral cats are released they usually vanish. If this guy is let go he may find his way back to the farm where he was trapped, or possibly find another free lunch counter where he will skulk in and out of shadows. He may also become coyote food. He will never be a cuddly lap cat but with time and patience Tom might be able to transition to a barn cat who knows where food is and a warm place to sleep is always available. We can only hope he can be domesticated to that level of tameness to live out his life.